playwright/browser_patches/webkit/patches/bootstrap.diff

diff --git a/Source/JavaScriptCore/CMakeLists.txt b/Source/JavaScriptCore/CMakeLists.txt
index 3dcce0f81ed..da640e5b4ba 100644
--- a/Source/JavaScriptCore/CMakeLists.txt
+++ b/Source/JavaScriptCore/CMakeLists.txt
@@ -1141,16 +1141,20 @@ set(JavaScriptCore_INSPECTOR_DOMAINS
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Animation.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/ApplicationCache.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Audit.json
+    ${JAVASCRIPTCORE_DIR}/inspector/protocol/Browser.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/CSS.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Canvas.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Console.json
+    ${JAVASCRIPTCORE_DIR}/inspector/protocol/Dialog.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/DOM.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/DOMDebugger.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/DOMStorage.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Database.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Debugger.json
+    ${JAVASCRIPTCORE_DIR}/inspector/protocol/Emulation.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/GenericTypes.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Heap.json
+    ${JAVASCRIPTCORE_DIR}/inspector/protocol/Input.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Inspector.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/LayerTree.json
     ${JAVASCRIPTCORE_DIR}/inspector/protocol/Network.json
diff --git a/Source/JavaScriptCore/DerivedSources.make b/Source/JavaScriptCore/DerivedSources.make
index e2a36fa8764..e3ed01ae7cf 100644
--- a/Source/JavaScriptCore/DerivedSources.make
+++ b/Source/JavaScriptCore/DerivedSources.make
@@ -241,16 +241,20 @@ INSPECTOR_DOMAINS := \
     $(JavaScriptCore)/inspector/protocol/Animation.json \
     $(JavaScriptCore)/inspector/protocol/ApplicationCache.json \
     $(JavaScriptCore)/inspector/protocol/Audit.json \
+    $(JavaScriptCore)/inspector/protocol/Browser.json \
     $(JavaScriptCore)/inspector/protocol/CSS.json \
     $(JavaScriptCore)/inspector/protocol/Canvas.json \
     $(JavaScriptCore)/inspector/protocol/Console.json \
+    $(JavaScriptCore)/inspector/protocol/Dialog.json \
     $(JavaScriptCore)/inspector/protocol/DOM.json \
     $(JavaScriptCore)/inspector/protocol/DOMDebugger.json \
     $(JavaScriptCore)/inspector/protocol/DOMStorage.json \
     $(JavaScriptCore)/inspector/protocol/Database.json \
     $(JavaScriptCore)/inspector/protocol/Debugger.json \
+    $(JavaScriptCore)/inspector/protocol/Emulation.json \
     $(JavaScriptCore)/inspector/protocol/GenericTypes.json \
     $(JavaScriptCore)/inspector/protocol/Heap.json \
+    $(JavaScriptCore)/inspector/protocol/Input.json \
     $(JavaScriptCore)/inspector/protocol/Inspector.json \
     $(JavaScriptCore)/inspector/protocol/LayerTree.json \
     $(JavaScriptCore)/inspector/protocol/Network.json \
diff --git a/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.cpp b/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.cpp
index 038cb646d31..8a01d7679bf 100644
--- a/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.cpp
+++ b/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.cpp
@@ -102,7 +102,7 @@ void BackendDispatcher::registerDispatcherForDomain(const String& domain, Supple
     m_dispatchers.set(domain, dispatcher);
 }
 
-void BackendDispatcher::dispatch(const String& message)
+BackendDispatcher::DispatchResult BackendDispatcher::dispatch(const String& message, Mode mode)
 {
     Ref<BackendDispatcher> protect(*this);
 
@@ -120,26 +120,26 @@ void BackendDispatcher::dispatch(const String& message)
         if (!JSON::Value::parseJSON(message, parsedMessage)) {
             reportProtocolError(ParseError, "Message must be in JSON format"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         if (!parsedMessage->asObject(messageObject)) {
             reportProtocolError(InvalidRequest, "Message must be a JSONified object"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         RefPtr<JSON::Value> requestIdValue;
         if (!messageObject->getValue("id"_s, requestIdValue)) {
             reportProtocolError(InvalidRequest, "'id' property was not found"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         if (!requestIdValue->asInteger(requestId)) {
             reportProtocolError(InvalidRequest, "The type of 'id' property must be integer"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
     }
 
@@ -151,29 +151,31 @@ void BackendDispatcher::dispatch(const String& message)
         if (!messageObject->getValue("method"_s, methodValue)) {
             reportProtocolError(InvalidRequest, "'method' property wasn't found"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         String methodString;
         if (!methodValue->asString(methodString)) {
             reportProtocolError(InvalidRequest, "The type of 'method' property must be string"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         Vector<String> domainAndMethod = methodString.splitAllowingEmptyEntries('.');
         if (domainAndMethod.size() != 2 || !domainAndMethod[0].length() || !domainAndMethod[1].length()) {
             reportProtocolError(InvalidRequest, "The 'method' property was formatted incorrectly. It should be 'Domain.method'"_s);
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         String domain = domainAndMethod[0];
         SupplementalBackendDispatcher* domainDispatcher = m_dispatchers.get(domain);
         if (!domainDispatcher) {
+            if (mode == Mode::ContinueIfDomainIsMissing)
+                return DispatchResult::Continue;
             reportProtocolError(MethodNotFound, "'" + domain + "' domain was not found");
             sendPendingErrors();
-            return;
+            return DispatchResult::Finished;
         }
 
         String method = domainAndMethod[1];
@@ -182,6 +184,7 @@ void BackendDispatcher::dispatch(const String& message)
         if (m_protocolErrors.size())
             sendPendingErrors();
     }
+    return DispatchResult::Finished;
 }
 
 // FIXME: remove this function when legacy InspectorObject symbols are no longer needed <http://webkit.org/b/179847>.
diff --git a/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.h b/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.h
index 95d9d81188e..6f96f174dff 100644
--- a/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.h
+++ b/Source/JavaScriptCore/inspector/InspectorBackendDispatcher.h
@@ -82,7 +82,10 @@ public:
     };
 
     void registerDispatcherForDomain(const String& domain, SupplementalBackendDispatcher*);
-    void dispatch(const String& message);
+
+    enum class DispatchResult { Finished, Continue };
+    enum class Mode { FailIfDomainIsMissing, ContinueIfDomainIsMissing };
+    DispatchResult dispatch(const String& message, Mode mode = Mode::FailIfDomainIsMissing);
 
     // Note that 'unused' is a workaround so the compiler can pick the right sendResponse based on arity.
     // When <http://webkit.org/b/179847> is fixed or this class is renamed for the JSON::Object case,
diff --git a/Source/JavaScriptCore/inspector/InspectorTarget.h b/Source/JavaScriptCore/inspector/InspectorTarget.h
index 4b95964db4d..e9a8079d513 100644
--- a/Source/JavaScriptCore/inspector/InspectorTarget.h
+++ b/Source/JavaScriptCore/inspector/InspectorTarget.h
@@ -45,8 +45,11 @@ public:
     // State.
     virtual String identifier() const = 0;
     virtual InspectorTargetType type() const = 0;
+    virtual String url() const = 0;
 
     virtual bool isProvisional() const { return false; }
+    virtual String oldTargetID() const { return String(); }
+    virtual String openerID() const { return String(); }
     bool isPaused() const { return m_isPaused; }
     void pause();
     void resume();
@@ -56,6 +59,8 @@ public:
     virtual void connect(FrontendChannel::ConnectionType) = 0;
     virtual void disconnect() = 0;
     virtual void sendMessageToTargetBackend(const String&) = 0;
+    virtual void activate(String& error) { error = "Target cannot be activated"; }
+    virtual void close(String& error) { error = "Target cannot be closed"; }
 
 private:
     WTF::Function<void()> m_resumeCallback;
diff --git a/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.cpp b/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.cpp
index 8fcb5a1e557..6363ca2d549 100644
--- a/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.cpp
+++ b/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.cpp
@@ -30,11 +30,12 @@
 
 namespace Inspector {
 
-InspectorTargetAgent::InspectorTargetAgent(FrontendRouter& frontendRouter, BackendDispatcher& backendDispatcher)
+InspectorTargetAgent::InspectorTargetAgent(FrontendRouter& frontendRouter, BackendDispatcher& backendDispatcher, const String& browserContextID)
     : InspectorAgentBase("Target"_s)
     , m_router(frontendRouter)
     , m_frontendDispatcher(makeUnique<TargetFrontendDispatcher>(frontendRouter))
     , m_backendDispatcher(TargetBackendDispatcher::create(backendDispatcher, this))
+    , m_browserContextID(browserContextID)
 {
 }
 
@@ -87,6 +88,28 @@ void InspectorTargetAgent::sendMessageToTarget(ErrorString& errorString, const S
     target->sendMessageToTargetBackend(message);
 }
 
+void InspectorTargetAgent::activate(ErrorString& errorString, const String& targetId)
+{
+    InspectorTarget* target = m_targets.get(targetId);
+    if (!target) {
+        errorString = "Missing target for given targetId"_s;
+        return;
+    }
+
+    target->activate(errorString);
+}
+
+void InspectorTargetAgent::close(ErrorString& errorString, const String& targetId)
+{
+    InspectorTarget* target = m_targets.get(targetId);
+    if (!target) {
+        errorString = "Missing target for given targetId"_s;
+        return;
+    }
+
+    target->close(errorString);
+}
+
 void InspectorTargetAgent::sendMessageFromTargetToFrontend(const String& targetId, const String& message)
 {
     ASSERT_WITH_MESSAGE(m_targets.get(targetId), "Sending a message from an untracked target to the frontend.");
@@ -109,16 +132,23 @@ static Protocol::Target::TargetInfo::Type targetTypeToProtocolType(InspectorTarg
     return Protocol::Target::TargetInfo::Type::Page;
 }
 
-static Ref<Protocol::Target::TargetInfo> buildTargetInfoObject(const InspectorTarget& target)
+static Ref<Protocol::Target::TargetInfo> buildTargetInfoObject(const InspectorTarget& target, const String& browserContextID)
 {
     auto result = Protocol::Target::TargetInfo::create()
         .setTargetId(target.identifier())
         .setType(targetTypeToProtocolType(target.type()))
+        .setUrl(target.url())
         .release();
-    if (target.isProvisional())
+    if (target.isProvisional()) {
         result->setIsProvisional(true);
+        result->setOldTargetId(target.oldTargetID());
+    }
     if (target.isPaused())
         result->setIsPaused(true);
+    if (!browserContextID.isEmpty())
+        result->setBrowserContextId(browserContextID);
+    if (!target.openerID().isEmpty())
+        result->setOpenerId(target.openerID());
     return result;
 }
 
@@ -134,7 +164,7 @@ void InspectorTargetAgent::targetCreated(InspectorTarget& target)
         target.pause();
     target.connect(connectionType());
 
-    m_frontendDispatcher->targetCreated(buildTargetInfoObject(target));
+    m_frontendDispatcher->targetCreated(buildTargetInfoObject(target, m_browserContextID));
 }
 
 void InspectorTargetAgent::targetDestroyed(InspectorTarget& target)
@@ -159,6 +189,18 @@ void InspectorTargetAgent::didCommitProvisionalTarget(const String& oldTargetID,
     m_frontendDispatcher->didCommitProvisionalTarget(oldTargetID, committedTargetID);
 }
 
+void InspectorTargetAgent::ensureConnected(const String& targetID)
+{
+    if (!m_isConnected)
+        return;
+
+    auto* target = m_targets.get(targetID);
+    if (!target)
+        return;
+
+    target->connect(connectionType());
+}
+
 FrontendChannel::ConnectionType InspectorTargetAgent::connectionType() const
 {
     return m_router.hasLocalFrontend() ? Inspector::FrontendChannel::ConnectionType::Local : Inspector::FrontendChannel::ConnectionType::Remote;
@@ -168,7 +210,7 @@ void InspectorTargetAgent::connectToTargets()
 {
     for (InspectorTarget* target : m_targets.values()) {
         target->connect(connectionType());
-        m_frontendDispatcher->targetCreated(buildTargetInfoObject(*target));
+        m_frontendDispatcher->targetCreated(buildTargetInfoObject(*target, m_browserContextID));
     }
 }
 
diff --git a/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.h b/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.h
index 1eb7abb2fa2..5a71d29af64 100644
--- a/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.h
+++ b/Source/JavaScriptCore/inspector/agents/InspectorTargetAgent.h
@@ -41,7 +41,7 @@ class JS_EXPORT_PRIVATE InspectorTargetAgent : public InspectorAgentBase, public
     WTF_MAKE_NONCOPYABLE(InspectorTargetAgent);
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    InspectorTargetAgent(FrontendRouter&, BackendDispatcher&);
+    InspectorTargetAgent(FrontendRouter&, BackendDispatcher&, const String& browserContextID);
     ~InspectorTargetAgent() override;
 
     // InspectorAgentBase
@@ -52,11 +52,14 @@ public:
     void setPauseOnStart(ErrorString&, bool pauseOnStart) override;
     void resume(ErrorString&, const String& targetId) override;
     void sendMessageToTarget(ErrorString&, const String& targetId, const String& message) final;
+    void activate(ErrorString&, const String& targetId) override;
+    void close(ErrorString&, const String& targetId) override;
 
     // Target lifecycle.
     void targetCreated(InspectorTarget&);
     void targetDestroyed(InspectorTarget&);
     void didCommitProvisionalTarget(const String& oldTargetID, const String& committedTargetID);
+    void ensureConnected(const String& targetID);
 
     // Target messages.
     void sendMessageFromTargetToFrontend(const String& targetId, const String& message);
@@ -70,6 +73,7 @@ private:
     Inspector::FrontendRouter& m_router;
     std::unique_ptr<TargetFrontendDispatcher> m_frontendDispatcher;
     Ref<TargetBackendDispatcher> m_backendDispatcher;
+    const String m_browserContextID;
     HashMap<String, InspectorTarget*> m_targets;
     bool m_isConnected { false };
     bool m_shouldPauseOnStart { false };
diff --git a/Source/JavaScriptCore/inspector/protocol/Browser.json b/Source/JavaScriptCore/inspector/protocol/Browser.json
new file mode 100644
index 00000000000..a51c3e1a6fe
--- /dev/null
+++ b/Source/JavaScriptCore/inspector/protocol/Browser.json
@@ -0,0 +1,114 @@
+{
+    "domain": "Browser",
+    "availability": ["web"],
+    "types": [
+        {
+            "id": "ContextID",
+            "type": "string",
+            "description": "Id of Browser context."
+        },
+        {
+            "id": "CookieSameSitePolicy",
+            "type": "string",
+            "enum": ["None", "Lax", "Strict"],
+            "description": "Same-Site policy of a cookie."
+        },
+        {
+            "id": "Cookie",
+            "type": "object",
+            "description": "Cookie object",
+            "properties": [
+                { "name": "name", "type": "string", "description": "Cookie name." },
+                { "name": "value", "type": "string", "description": "Cookie value." },
+                { "name": "domain", "type": "string", "description": "Cookie domain." },
+                { "name": "path", "type": "string", "description": "Cookie path." },
+                { "name": "expires", "type": "number", "description": "Cookie expires." },
+                { "name": "httpOnly", "type": "boolean", "description": "True if cookie is http-only." },
+                { "name": "secure", "type": "boolean", "description": "True if cookie is secure." },
+                { "name": "session", "type": "boolean", "description": "True if cookie is session cookie." },
+                { "name": "sameSite", "$ref": "CookieSameSitePolicy", "description": "Cookie Same-Site policy." }
+            ]
+        },
+        {
+            "id": "SetCookieParam",
+            "type": "object",
+            "description": "Cookie object",
+            "properties": [
+                { "name": "name", "type": "string", "description": "Cookie name." },
+                { "name": "value", "type": "string", "description": "Cookie value." },
+                { "name": "domain", "type": "string", "description": "Cookie domain." },
+                { "name": "path", "type": "string", "description": "Cookie path." },
+                { "name": "expires", "type": "number", "optional": true, "description": "Cookie expires." },
+                { "name": "httpOnly", "type": "boolean", "optional": true, "description": "True if cookie is http-only." },
+                { "name": "secure", "type": "boolean", "optional": true, "description": "True if cookie is secure." },
+                { "name": "session", "type": "boolean", "optional": true, "description": "True if cookie is session cookie." },
+                { "name": "sameSite", "$ref": "CookieSameSitePolicy", "optional": true, "description": "Cookie Same-Site policy." }
+            ]
+        }
+    ],
+    "commands": [
+        {
+            "name": "close",
+            "description": "Close browser."
+        },
+        {
+            "name": "createContext",
+            "description": "Creates new ephemeral browser context.",
+            "returns": [
+                { "name": "browserContextId", "$ref": "ContextID", "description": "Unique identifier of the context." }
+            ]
+        },
+        {
+            "name": "deleteContext",
+            "description": "Deletes browser context previously created with createContect. The command will automatically close all pages that use the context.",
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "description": "Identifier of the context to delete." }
+            ]
+        },
+        {
+            "name": "createPage",
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "optional": true, "description": "JSON Inspector Protocol message (command) to be dispatched on the backend." }
+            ],
+            "returns": [
+                { "name": "targetId", "type": "string", "description": "Unique identifier for the page target." }
+            ]
+        },
+        {
+            "name": "setIgnoreCertificateErrors",
+            "description": "Change whether all certificate errors should be ignored.",
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "optional": true, "description": "Browser context id." },
+                { "name": "ignore", "type": "boolean" }
+            ]
+        },
+        {
+            "name": "getAllCookies",
+            "description": "Returns all cookies in the given browser context.",
+            "async": true,
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "optional": true, "description": "Browser context id." }
+            ],
+            "returns": [
+                { "name": "cookies", "type": "array", "items": { "$ref": "Cookie" }, "description": "Cookies." }
+            ]
+        },
+        {
+            "name": "setCookies",
+            "description": "Sets cookies in the given browser context.",
+            "async": true,
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "optional": true, "description": "Browser context id." },
+                { "name": "cookies", "type": "array", "items": { "$ref": "SetCookieParam" }, "description": "Cookies." }
+            ]
+        },
+        {
+            "name": "deleteAllCookies",
+            "description": "Deletes cookies in the given browser context.",
+            "async": true,
+            "parameters": [
+                { "name": "browserContextId", "$ref": "ContextID", "optional": true, "description": "Browser context id." }
+            ]
+        }
+    ]
+}
diff --git a/Source/JavaScriptCore/inspector/protocol/DOM.json b/Source/JavaScriptCore/inspector/protocol/DOM.json
index 38cb48bedf2..b23e12c5d00 100644
--- a/Source/JavaScriptCore/inspector/protocol/DOM.json
+++ b/Source/JavaScriptCore/inspector/protocol/DOM.json
@@ -167,6 +167,16 @@
                 { "name": "borderColor", "$ref": "RGBAColor", "optional": true, "description": "The border highlight fill color (default: transparent)." },
                 { "name": "marginColor", "$ref": "RGBAColor", "optional": true, "description": "The margin highlight fill color (default: transparent)." }
             ]
+        },
+        {
+            "id": "FilePayload",
+            "type": "object",
+            "description": "Data to construct File object.",
+            "properties": [
+                { "name": "name", "type": "string", "description": "File name." },
+                { "name": "type", "type": "string", "description": "File type." },
+                { "name": "data", "type": "string", "description": "Base64-encoded file data." }
+            ]
         }
     ],
     "commands": [
@@ -481,7 +491,9 @@
             "name": "resolveNode",
             "description": "Resolves JavaScript node object for given node id.",
             "parameters": [
-                { "name": "nodeId", "$ref": "NodeId", "description": "Id of the node to resolve." },
+                { "name": "nodeId", "$ref": "NodeId", "optional": true, "description": "Id of the node to resolve." },
+                { "name": "objectId", "$ref": "Runtime.RemoteObjectId", "optional": true, "description": "Source element handle." },
+                { "name": "executionContextId", "$ref": "Runtime.ExecutionContextId", "optional": true, "description": "Specifies in which execution context to adopt to." },
                 { "name": "objectGroup", "type": "string", "optional": true, "description": "Symbolic group name that can be used to release multiple objects." }
             ],
             "returns": [
@@ -542,6 +554,26 @@
             "parameters": [
                 { "name": "allow", "type": "boolean" }
             ]
+        },
+        {
+            "name": "getContentQuads",
+            "description": "Returns quads that describe node position on the page. This method\nmight return multiple quads for inline nodes.",
+            "parameters": [
+                { "name": "objectId", "description": "JavaScript object id of the node wrapper.", "$ref": "Runtime.RemoteObjectId" }
+            ],
+            "returns": [
+                {
+                    "name": "quads", "description": "Quads that describe node layout relative to viewport.", "type": "array", "items": { "$ref": "Quad" }
+                }
+            ]
+        },
+        {
+            "name": "setInputFiles",
+            "description": "Sets input files for given <input type=file>",
+            "parameters": [
+                { "name": "objectId", "$ref": "Runtime.RemoteObjectId", "description": "Input element handle." },
+                { "name": "files", "type": "array", "items": { "$ref": "FilePayload" }, "description": "Files to set" }
+            ]
         }
     ],
     "events": [
diff --git a/Source/JavaScriptCore/inspector/protocol/Dialog.json b/Source/JavaScriptCore/inspector/protocol/Dialog.json
new file mode 100644
index 00000000000..79edea03fed
--- /dev/null
+++ b/Source/JavaScriptCore/inspector/protocol/Dialog.json
@@ -0,0 +1,36 @@
+{
+    "domain": "Dialog",
+    "description": "Actions and events related to alert boxes.",
+    "availability": ["web"],
+    "types": [
+    ],
+    "commands": [
+        {
+            "name": "enable",
+            "description": "Enables dialog domain notifications."
+        },
+        {
+            "name": "disable",
+            "description": "Disables dialog domain notifications."
+        },
+        {
+            "name": "handleJavaScriptDialog",
+            "description": "Accepts or dismisses a JavaScript initiated dialog (alert, confirm, prompt, or onbeforeunload).",
+            "parameters": [
+                { "name": "accept", "type": "boolean", "description": "Whether to accept or dismiss the dialog."},
+                { "name": "promptText", "optional": true, "type": "string", "description": "The text to enter into the dialog prompt before accepting. Used only if this is a prompt dialog."}
+            ]
+        }
+    ],
+    "events": [
+        {
+            "name": "javascriptDialogOpening",
+            "description": "Fired when a JavaScript initiated dialog (alert, confirm, prompt, or onbeforeunload) is about to open.",
+            "parameters": [
+                { "name": "type", "type": "string", "description": "Dialog type."},
+                { "name": "message", "type": "string", "description": "Message that will be displayed by the dialog."},
+                { "name": "defaultPrompt", "optional": true, "type": "string", "description": "Default dialog prompt."}
+            ]
+        }
+    ]
+}
diff --git a/Source/JavaScriptCore/inspector/protocol/Emulation.json b/Source/JavaScriptCore/inspector/protocol/Emulation.json
new file mode 100644
index 00000000000..7133fb577e2
--- /dev/null
+++ b/Source/JavaScriptCore/inspector/protocol/Emulation.json
@@ -0,0 +1,23 @@
+{
+    "domain": "Emulation",
+    "availability": ["web"],
+    "commands": [
+        {
+            "name": "setDeviceMetricsOverride",
+            "description": "Overrides device metrics with provided values.",
+            "async": true,
+            "parameters": [
+                { "name": "width", "type": "integer" },
+                { "name": "height", "type": "integer" },
+                { "name": "deviceScaleFactor", "type": "number" }
+            ]
+        },
+        {
+            "name": "setJavaScriptEnabled",
+            "description": "Allows to disable script execution for the page.",
+            "parameters": [
+                { "name": "enabled", "type": "boolean" }
+            ]
+        }
+    ]
+}
diff --git a/Source/JavaScriptCore/inspector/protocol/Input.json b/Source/JavaScriptCore/inspector/protocol/Input.json
new file mode 100644
index 00000000000..60515155c22
--- /dev/null
+++ b/Source/JavaScriptCore/inspector/protocol/Input.json
@@ -0,0 +1,169 @@
+{
+    "domain": "Input",
+    "availability": ["web"],
+    "types": [
+        {
+            "id": "TimeSinceEpoch",
+            "description": "UTC time in seconds, counted from January 1, 1970.",
+            "type": "number"
+        }
+    ],
+    "commands": [
+        {
+            "name": "goBack",
+            "description": "FIXME: move this to Page domain."
+        },
+        {
+            "name": "dispatchKeyEvent",
+            "description": "Dispatches a key event to the page.",
+            "async": true,
+            "parameters": [
+                {
+                    "name": "type",
+                    "description": "Type of the key event.",
+                    "type": "string",
+                    "enum": [
+                        "keyDown",
+                        "keyUp"
+                    ]
+                },
+                {
+                    "name": "modifiers",
+                    "description": "Bit field representing pressed modifier keys. (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "text",
+                    "description": "Text as generated by processing a virtual key code with a keyboard layout. Not needed for\nfor `keyUp` and `rawKeyDown` events (default: \"\")",
+                    "optional": true,
+                    "type": "string"
+                },
+                {
+                    "name": "unmodifiedText",
+                    "description": "Text that would have been generated by the keyboard if no modifiers were pressed (except for\nshift). Useful for shortcut (accelerator) key handling (default: \"\").",
+                    "optional": true,
+                    "type": "string"
+                },
+                {
+                    "name": "code",
+                    "description": "Unique DOM defined string value for each physical key (e.g., 'KeyA') (default: \"\").",
+                    "optional": true,
+                    "type": "string"
+                },
+                {
+                    "name": "key",
+                    "description": "Unique DOM defined string value describing the meaning of the key in the context of active\nmodifiers, keyboard layout, etc (e.g., 'AltGr') (default: \"\").",
+                    "optional": true,
+                    "type": "string"
+                },
+                {
+                    "name": "windowsVirtualKeyCode",
+                    "description": "Windows virtual key code (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "nativeVirtualKeyCode",
+                    "description": "Native virtual key code (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "autoRepeat",
+                    "description": "Whether the event was generated from auto repeat (default: false).",
+                    "optional": true,
+                    "type": "boolean"
+                },
+                {
+                    "name": "isKeypad",
+                    "description": "Whether the event was generated from the keypad (default: false).",
+                    "optional": true,
+                    "type": "boolean"
+                },
+                {
+                    "name": "isSystemKey",
+                    "description": "Whether the event was a system key event (default: false).",
+                    "optional": true,
+                    "type": "boolean"
+                },
+                {
+                    "name": "macCommands",
+                    "description": "Mac editing commands associated with this key",
+                    "type": "array",
+                    "optional": true,
+                    "items": {
+                      "type": "string"
+                    }
+                }
+            ]
+        },
+        {
+            "name": "dispatchMouseEvent",
+            "description": "Dispatches a mouse event to the page.",
+            "async": true,
+            "parameters": [
+                {
+                    "name": "type",
+                    "description": "Type of the mouse event.",
+                    "type": "string",
+                    "enum": [ "move", "down", "up", "wheel"]
+                },
+                {
+                    "name": "x",
+                    "description": "X coordinate of the event relative to the main frame's viewport in CSS pixels.",
+                    "type": "integer"
+                },
+                {
+                    "name": "y",
+                    "description": "Y coordinate of the event relative to the main frame's viewport in CSS pixels. 0 refers to\nthe top of the viewport and Y increases as it proceeds towards the bottom of the viewport.",
+                    "type": "integer"
+                },
+                {
+                    "name": "modifiers",
+                    "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8\n(default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "button",
+                    "description": "Mouse button (default: \"none\").",
+                    "optional": true,
+                    "type": "string",
+                    "enum": [
+                        "none",
+                        "left",
+                        "middle",
+                        "right",
+                        "back",
+                        "forward"
+                    ]
+                },
+                {
+                    "name": "buttons",
+                    "description": "A number indicating which buttons are pressed on the mouse when a mouse event is triggered.\nLeft=1, Right=2, Middle=4, Back=8, Forward=16, None=0.",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "clickCount",
+                    "description": "Number of times the mouse button was clicked (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "deltaX",
+                    "description": "X delta in CSS pixels for mouse wheel event (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                },
+                {
+                    "name": "deltaY",
+                    "description": "Y delta in CSS pixels for mouse wheel event (default: 0).",
+                    "optional": true,
+                    "type": "integer"
+                }
+            ]
+        }
+    ]
+}
diff --git a/Source/JavaScriptCore/inspector/protocol/Page.json b/Source/JavaScriptCore/inspector/protocol/Page.json
index 367d1f235a8..f5bdf41aad8 100644
--- a/Source/JavaScriptCore/inspector/protocol/Page.json
+++ b/Source/JavaScriptCore/inspector/protocol/Page.json
@@ -108,6 +108,40 @@
                 { "name": "session", "type": "boolean", "description": "True in case of session cookie." },
                 { "name": "sameSite", "$ref": "CookieSameSitePolicy", "description": "Cookie Same-Site policy." }
             ]
+        },
+        {
+            "id": "AXNode",
+            "type": "object",
+            "description": "Accessibility Node",
+            "properties": [
+                { "name": "role", "type": "string", "description": "The role."},
+                { "name": "name", "type": "string","optional": true, "description": "A human readable name for the node."},
+                { "name": "value", "type": "any", "optional": true, "description": "The current value of the node."},
+                { "name": "description", "type": "string", "optional": true, "description": "An additional human readable description of the node."},
+                { "name": "keyshortcuts", "type": "string", "optional": true, "description": "Keyboard shortcuts associated with this node."},
+                { "name": "roledescription", "type": "string", "optional": true, "description": "A human readable alternative to the role."},
+                { "name": "valuetext", "type": "string", "optional": true, "description": "A description of the current value."},
+                { "name": "disabled", "type": "boolean", "optional": true, "description": "Whether the node is disabled."},
+                { "name": "expanded", "type": "boolean", "optional": true, "description": "Whether the node is expanded or collapsed."},
+                { "name": "focused", "type": "boolean", "optional": true, "description": "Whether the node is focused."},
+                { "name": "modal", "type": "boolean", "optional": true, "description": "Whether the node is modal."},
+                { "name": "multiline", "type": "boolean", "optional": true, "description": "Whether the node text input supports multiline."},
+                { "name": "multiselectable", "type": "boolean", "optional": true, "description": "Whether more than one child can be selected."},
+                { "name": "readonly", "type": "boolean", "optional": true, "description": "Whether the node is read only."},
+                { "name": "required", "type": "boolean", "optional": true, "description": "Whether the node is required."},
+                { "name": "selected", "type": "boolean", "optional": true, "description": "Whether the node is selected in its parent node."},
+                { "name": "checked", "type": "string", "optional": true, "enum": ["true", "false", "mixed"], "description": "Whether the checkbox is checked, or \"mixed\"."},
+                { "name": "pressed", "type": "string", "optional": true, "enum": ["true", "false", "mixed"], "description": "Whether the toggle button is checked, or \"mixed\"."},
+                { "name": "level", "type": "integer", "optional": true, "description": "The level of a heading."},
+                { "name": "valuemin", "type": "number", "optional": true, "description": "The minimum value in a node."},
+                { "name": "valuemax", "type": "number", "optional": true, "description": "The maximum value in a node."},
+                { "name": "autocomplete", "type": "string", "optional": true, "description": "What kind of autocomplete is supported by a control."},
+                { "name": "haspopup", "type": "string", "optional": true, "description": "What kind of popup is currently being shown for a node."},
+                { "name": "invalid", "type": "string", "optional": true, "enum": ["true", "false", "grammar", "spelling"], "description": "Whether and in what way this node's value is invalid."},
+                { "name": "orientation", "type": "string", "optional": true, "description": "Whether the node is oriented horizontally or vertically."},
+                { "name": "focusable", "type": "boolean", "optional": true, "description": "Whether the node is focusable."},
+                { "name": "children", "type": "array", "optional": true, "items": { "$ref": "AXNode"}, "description": "Child AXNodes of this node, if any."}
+            ]
         }
     ],
     "commands": [
@@ -127,11 +161,20 @@
                 { "name": "revalidateAllResources", "type": "boolean", "optional": true, "description": "If true, all cached subresources will be revalidated when the main resource loads. Otherwise, only expired cached subresources will be revalidated (the default behavior for most WebKit clients)." }
             ]
         },
+        {
+            "name": "goBack",
+            "description": "Goes back in the history."
+        },
+        {
+            "name": "goForward",
+            "description": "Goes forward in the history."
+        },
         {
             "name": "navigate",
             "description": "Navigates current page to the given URL.",
             "parameters": [
-                { "name": "url", "type": "string", "description": "URL to navigate the page to." }
+                { "name": "url", "type": "string", "description": "URL to navigate the page to." },
+                { "name": "frameId", "$ref": "Network.FrameId", "optional": true, "description": "Id of the frame to navigate."}
             ]
         },
         {
@@ -288,19 +331,64 @@
             "returns": [
                 { "name": "data", "type": "string", "description": "Base64-encoded web archive." }
             ]
+        },
+        {
+            "name": "insertText",
+            "description": "Insert text into the current selection of the page.",
+            "parameters": [
+                { "name": "text", "type": "string", "description": "Text to insert." }
+            ]
+        },
+        {
+            "name": "accessibilitySnapshot",
+            "description": "Serializes and returns all of the accessibility nodes of the page.",
+            "returns": [
+                { "name": "axNode", "$ref": "AXNode", "description": "The root AXNode."}
+            ]
+        },
+        {
+            "name": "setInterceptFileChooserDialog",
+            "description": "Intercepts file chooser dialog",
+            "parameters": [
+                { "name": "enabled", "type": "boolean", "description": "True to enable." }
+            ]
+        },
+        {
+            "name": "setDefaultBackgroundColorOverride",
+            "description": "Sets or clears an override of the default background color of the frame. This override is used if the content does not specify one.",
+            "parameters": [
+                { "name": "color", "$ref": "DOM.RGBAColor", "optional": true, "description": "RGBA of the default background color. If not specified, any existing override will be cleared." }
+            ]
+        },
+        {
+            "name": "createIsolatedWorld",
+            "description": "Creates an isolated world for every loaded frame.",
+            "parameters": [
+                { "name": "name", "type": "string", "description": "Isolated world name, will be used as an execution context name." },
+                { "name": "source", "type": "string", "optional": true, "description": "Script to evaluate in the new world." }
+            ]
+        },
+        {
+            "name": "setBypassCSP",
+            "description": "Enable page Content Security Policy by-passing.",
+            "parameters": [
+                { "name": "enabled", "type": "boolean", "description": "Whether to bypass page CSP." }
+            ]
         }
     ],
     "events": [
         {
             "name": "domContentEventFired",
             "parameters": [
-                { "name": "timestamp", "type": "number" }
+                { "name": "timestamp", "type": "number" },
+                { "name": "frameId", "$ref": "Network.FrameId", "description": "Id of the frame that has fired DOMContentLoaded event." }
             ]
         },
         {
             "name": "loadEventFired",
             "parameters": [
-                { "name": "timestamp", "type": "number" }
+              { "name": "timestamp", "type": "number" },
+              { "name": "frameId", "$ref": "Network.FrameId", "description": "Id of the frame that has fired load event." }
             ]
         },
         {
@@ -310,6 +398,14 @@
                 { "name": "frame", "$ref": "Frame", "description": "Frame object." }
             ]
         },
+        {
+          "name": "frameAttached",
+          "description": "Fired when frame has been attached to its parent.",
+          "parameters": [
+              { "name": "frameId", "$ref": "Network.FrameId", "description": "Id of the frame that has been detached." },
+              { "name": "parentFrameId", "$ref": "Network.FrameId", "optional": true, "description": "Parent frame id if non-root." }
+          ]
+        },
         {
             "name": "frameDetached",
             "description": "Fired when frame has been detached from its parent.",
@@ -346,12 +442,36 @@
                 { "name": "frameId", "$ref": "Network.FrameId", "description": "Id of the frame that has cleared its scheduled navigation." }
             ]
         },
+        {
+            "name": "navigatedWithinDocument",
+            "description": "Fired when same-document navigation happens, e.g. due to history API usage or anchor navigation.",
+            "parameters": [
+                {
+                    "name": "frameId",
+                    "description": "Id of the frame.",
+                    "$ref": "Network.FrameId"
+                },
+                {
+                    "name": "url",
+                    "description": "Frame's new url.",
+                    "type": "string"
+                }
+            ]
+        },
         {
             "name": "defaultAppearanceDidChange",
             "description": "Fired when page's default appearance changes, even if there is a forced appearance.",
             "parameters": [
                 { "name": "appearance", "$ref": "Appearance", "description": "Name of the appearance that is active (not considering any forced appearance.)" }
             ]
+        },
+        {
+            "name": "fileChooserOpened",
+            "description": "Fired when the page shows file chooser for it's <input type=file>.",
+            "parameters": [
+                { "name": "frameId", "$ref": "Network.FrameId", "description": "Frame where file chooser is opened." },
+                { "name": "element", "$ref": "Runtime.RemoteObject", "description": "Input element." }
+            ]
         }
     ]
 }
diff --git a/Source/JavaScriptCore/inspector/protocol/Target.json b/Source/JavaScriptCore/inspector/protocol/Target.json
index 52920cded24..30bcc1d463e 100644
--- a/Source/JavaScriptCore/inspector/protocol/Target.json
+++ b/Source/JavaScriptCore/inspector/protocol/Target.json
@@ -10,8 +10,12 @@
             "properties": [
                 { "name": "targetId", "type": "string", "description": "Unique identifier for the target." },
                 { "name": "type", "type": "string", "enum": ["page", "service-worker", "worker"] },
-                { "name": "isProvisional", "type": "boolean", "optional": true, "description": "Whether this is a provisional page target." },
-                { "name": "isPaused", "type": "boolean", "optional": true, "description": "Whether the target is paused on start and has to be explicitely resumed by inspector." }
+                { "name": "isProvisional", "type": "boolean", "optional": true, "description": "True value indicates that this is a provisional page target i.e. Such target may be created when current page starts cross-origin navigation. Eventually each provisional target is either committed and swaps with the current target or gets destroyed, e.g. in case of load request failure." },
+                { "name": "oldTargetId", "type": "string", "optional": true, "description": "Unique identifier of the target which is going to be replaced if this target is committed. Only set for provisional targets." },
+                { "name": "openerId", "type": "string", "optional": true, "description": "Unique identifier of the opening target. Only set for pages created by window.open()." },
+                { "name": "isPaused", "type": "boolean", "optional": true, "description": "Whether the target is paused on start and has to be explicitely resumed by inspector." },
+                { "name": "url", "type": "string" },
+                { "name": "browserContextId", "$ref": "Browser.ContextID", "optional": true }
             ]
         }
     ],
@@ -37,6 +41,20 @@
                 { "name": "targetId", "type": "string" },
                 { "name": "message", "type": "string", "description": "JSON Inspector Protocol message (command) to be dispatched on the backend." }
             ]
+        },
+        {
+            "name": "activate",
+            "description": "Reveals the target on screen.",
+            "parameters": [
+                { "name": "targetId", "type": "string" }
+            ]
+        },
+        {
+            "name": "close",
+            "description": "Closes the target.",
+            "parameters": [
+                { "name": "targetId", "type": "string" }
+            ]
         }
     ],
     "events": [
diff --git a/Source/WebCore/html/FileInputType.cpp b/Source/WebCore/html/FileInputType.cpp
index 4e41fd3f807..1f7be602cb2 100644
--- a/Source/WebCore/html/FileInputType.cpp
+++ b/Source/WebCore/html/FileInputType.cpp
@@ -36,6 +36,7 @@
 #include "HTMLNames.h"
 #include "Icon.h"
 #include "InputTypeNames.h"
+#include "InspectorInstrumentation.h"
 #include "LocalizedStrings.h"
 #include "RenderFileUploadControl.h"
 #include "RuntimeEnabledFeatures.h"
@@ -205,6 +206,11 @@ void FileInputType::handleDOMActivateEvent(Event& event)
     if (input.isDisabledFormControl())
         return;
 
+    bool intercept = false;
+    InspectorInstrumentation::runOpenPanel(input.document().frame(), element(), &intercept);
+    if (intercept)
+        return;
+
     if (!UserGestureIndicator::processingUserGesture())
         return;
 
diff --git a/Source/WebCore/inspector/InspectorInstrumentation.cpp b/Source/WebCore/inspector/InspectorInstrumentation.cpp
index 4f18b58c6cd..66ce7d20b32 100644
--- a/Source/WebCore/inspector/InspectorInstrumentation.cpp
+++ b/Source/WebCore/inspector/InspectorInstrumentation.cpp
@@ -121,7 +121,7 @@ static Frame* frameForScriptExecutionContext(ScriptExecutionContext& context)
 
 void InspectorInstrumentation::didClearWindowObjectInWorldImpl(InstrumentingAgents& instrumentingAgents, Frame& frame, DOMWrapperWorld& world)
 {
-    if (&world != &mainThreadNormalWorld())
+    if (!world.isNormal())
         return;
 
     if (auto* pageDebuggerAgent = instrumentingAgents.pageDebuggerAgent())
@@ -656,20 +656,17 @@ void InspectorInstrumentation::didReceiveScriptResponseImpl(InstrumentingAgents&
 
 void InspectorInstrumentation::domContentLoadedEventFiredImpl(InstrumentingAgents& instrumentingAgents, Frame& frame)
 {
-    if (!frame.isMainFrame())
-        return;
-
     if (InspectorPageAgent* pageAgent = instrumentingAgents.inspectorPageAgent())
-        pageAgent->domContentEventFired();
+        pageAgent->domContentEventFired(frame);
 }
 
 void InspectorInstrumentation::loadEventFiredImpl(InstrumentingAgents& instrumentingAgents, Frame* frame)
 {
-    if (!frame || !frame->isMainFrame())
+    if (!frame)
         return;
 
     if (InspectorPageAgent* pageAgent = instrumentingAgents.inspectorPageAgent())
-        pageAgent->loadEventFired();
+        pageAgent->loadEventFired(*frame);
 }
 
 void InspectorInstrumentation::frameDetachedFromParentImpl(InstrumentingAgents& instrumentingAgents, Frame& frame)
@@ -786,6 +783,12 @@ void InspectorInstrumentation::frameClearedScheduledNavigationImpl(Instrumenting
         inspectorPageAgent->frameClearedScheduledNavigation(frame);
 }
 
+void InspectorInstrumentation::didNavigateWithinPageImpl(InstrumentingAgents& instrumentingAgents, Frame& frame)
+{
+    if (InspectorPageAgent* inspectorPageAgent = instrumentingAgents.inspectorPageAgent())
+        inspectorPageAgent->didNavigateWithinPage(frame);
+}
+
 void InspectorInstrumentation::defaultAppearanceDidChangeImpl(InstrumentingAgents& instrumentingAgents, bool useDarkAppearance)
 {
     if (InspectorPageAgent* inspectorPageAgent = instrumentingAgents.inspectorPageAgent())
@@ -1266,6 +1269,24 @@ void InspectorInstrumentation::renderLayerDestroyedImpl(InstrumentingAgents& ins
         layerTreeAgent->renderLayerDestroyed(renderLayer);
 }
 
+void InspectorInstrumentation::runOpenPanelImpl(InstrumentingAgents& instrumentingAgents, HTMLInputElement* element, bool* intercept)
+{
+    if (InspectorPageAgent* pageAgent = instrumentingAgents.inspectorPageAgent())
+        pageAgent->runOpenPanel(element, intercept);
+}
+
+void InspectorInstrumentation::frameAttachedImpl(InstrumentingAgents& instrumentingAgents, Frame& frame) {
+    if (InspectorPageAgent* pageAgent = instrumentingAgents.inspectorPageAgent())
+        pageAgent->frameAttached(frame);
+}
+
+bool InspectorInstrumentation::shouldBypassCSPImpl(InstrumentingAgents& instrumentingAgents)
+{
+    if (InspectorPageAgent* pageAgent = instrumentingAgents.inspectorPageAgent())
+        return pageAgent->shouldBypassCSP();
+    return false;
+}
+
 InstrumentingAgents& InspectorInstrumentation::instrumentingAgentsForWorkerGlobalScope(WorkerGlobalScope& workerGlobalScope)
 {
     return workerGlobalScope.inspectorController().m_instrumentingAgents;
diff --git a/Source/WebCore/inspector/InspectorInstrumentation.h b/Source/WebCore/inspector/InspectorInstrumentation.h
index dbf82205db5..e11172818f1 100644
--- a/Source/WebCore/inspector/InspectorInstrumentation.h
+++ b/Source/WebCore/inspector/InspectorInstrumentation.h
@@ -77,6 +77,7 @@ class DOMWrapperWorld;
 class Document;
 class DocumentLoader;
 class EventListener;
+class HTMLInputElement;
 class HTTPHeaderMap;
 class InspectorTimelineAgent;
 class InstrumentingAgents;
@@ -228,6 +229,7 @@ public:
     static void frameStoppedLoading(Frame&);
     static void frameScheduledNavigation(Frame&, Seconds delay);
     static void frameClearedScheduledNavigation(Frame&);
+    static void didNavigateWithinPage(Frame&);
     static void defaultAppearanceDidChange(Page&, bool useDarkAppearance);
     static void willDestroyCachedResource(CachedResource&);
 
@@ -314,6 +316,10 @@ public:
     static void layerTreeDidChange(Page*);
     static void renderLayerDestroyed(Page*, const RenderLayer&);
 
+    static void runOpenPanel(Frame*, HTMLInputElement*, bool*);
+    static void frameAttached(Frame*);
+    static bool shouldBypassCSP(ScriptExecutionContext*);
+
     static void frontendCreated();
     static void frontendDeleted();
     static bool hasFrontends() { return InspectorInstrumentationPublic::hasFrontends(); }
@@ -429,6 +435,7 @@ private:
     static void frameStoppedLoadingImpl(InstrumentingAgents&, Frame&);
     static void frameScheduledNavigationImpl(InstrumentingAgents&, Frame&, Seconds delay);
     static void frameClearedScheduledNavigationImpl(InstrumentingAgents&, Frame&);
+    static void didNavigateWithinPageImpl(InstrumentingAgents&, Frame&);
     static void defaultAppearanceDidChangeImpl(InstrumentingAgents&, bool useDarkAppearance);
     static void willDestroyCachedResourceImpl(CachedResource&);
 
@@ -511,6 +518,10 @@ private:
     static void layerTreeDidChangeImpl(InstrumentingAgents&);
     static void renderLayerDestroyedImpl(InstrumentingAgents&, const RenderLayer&);
 
+    static void runOpenPanelImpl(InstrumentingAgents&, HTMLInputElement*, bool*);
+    static void frameAttachedImpl(InstrumentingAgents&, Frame&);
+    static bool shouldBypassCSPImpl(InstrumentingAgents&);
+
     static InstrumentingAgents& instrumentingAgentsForPage(Page&);
     static InstrumentingAgents& instrumentingAgentsForWorkerGlobalScope(WorkerGlobalScope&);
 
@@ -1221,6 +1232,13 @@ inline void InspectorInstrumentation::frameClearedScheduledNavigation(Frame& fra
         frameClearedScheduledNavigationImpl(*instrumentingAgents, frame);
 }
 
+inline void InspectorInstrumentation::didNavigateWithinPage(Frame& frame)
+{
+    FAST_RETURN_IF_NO_FRONTENDS(void());
+    if (InstrumentingAgents* instrumentingAgents = instrumentingAgentsForFrame(frame))
+        didNavigateWithinPageImpl(*instrumentingAgents, frame);
+}
+
 inline void InspectorInstrumentation::defaultAppearanceDidChange(Page& page, bool useDarkAppearance)
 {
     FAST_RETURN_IF_NO_FRONTENDS(void());
@@ -1650,6 +1668,28 @@ inline void InspectorInstrumentation::renderLayerDestroyed(Page* page, const Ren
         renderLayerDestroyedImpl(*instrumentingAgents, renderLayer);
 }
 
+inline void InspectorInstrumentation::runOpenPanel(Frame* frame, HTMLInputElement* element, bool* intercept)
+{
+    FAST_RETURN_IF_NO_FRONTENDS(void());
+    if (InstrumentingAgents* instrumentingAgents = instrumentingAgentsForFrame(*frame))
+        runOpenPanelImpl(*instrumentingAgents, element, intercept);
+}
+
+inline void InspectorInstrumentation::frameAttached(Frame* frame)
+{
+    FAST_RETURN_IF_NO_FRONTENDS(void());
+    if (InstrumentingAgents* instrumentingAgents = instrumentingAgentsForFrame(frame))
+        frameAttachedImpl(*instrumentingAgents, *frame);
+}
+
+inline bool InspectorInstrumentation::shouldBypassCSP(ScriptExecutionContext* context)
+{
+    FAST_RETURN_IF_NO_FRONTENDS(false);
+    if (InstrumentingAgents* instrumentingAgents = instrumentingAgentsForContext(context))
+        return shouldBypassCSPImpl(*instrumentingAgents);
+    return false;
+}
+
 inline InstrumentingAgents* InspectorInstrumentation::instrumentingAgentsForContext(ScriptExecutionContext* context)
 {
     return context ? instrumentingAgentsForContext(*context) : nullptr;
diff --git a/Source/WebCore/inspector/agents/InspectorDOMAgent.cpp b/Source/WebCore/inspector/agents/InspectorDOMAgent.cpp
index aecc79bc0ca..fb2460b2121 100644
--- a/Source/WebCore/inspector/agents/InspectorDOMAgent.cpp
+++ b/Source/WebCore/inspector/agents/InspectorDOMAgent.cpp
@@ -61,12 +61,16 @@
 #include "Event.h"
 #include "EventListener.h"
 #include "EventNames.h"
+#include "File.h"
+#include "FileList.h"
 #include "Frame.h"
 #include "FrameTree.h"
 #include "FrameView.h"
 #include "FullscreenManager.h"
+#include "FloatQuad.h"
 #include "HTMLElement.h"
 #include "HTMLFrameOwnerElement.h"
+#include "HTMLInputElement.h"
 #include "HTMLMediaElement.h"
 #include "HTMLNames.h"
 #include "HTMLParserIdioms.h"
@@ -93,11 +97,13 @@
 #include "Page.h"
 #include "Pasteboard.h"
 #include "PseudoElement.h"
+#include "RenderObject.h"
 #include "RenderStyle.h"
 #include "RenderStyleConstants.h"
 #include "ScriptState.h"
 #include "SelectorChecker.h"
 #include "ShadowRoot.h"
+#include "SharedBuffer.h"
 #include "StaticNodeList.h"
 #include "StyleProperties.h"
 #include "StyleResolver.h"
@@ -128,7 +134,8 @@ using namespace HTMLNames;
 static const size_t maxTextSize = 10000;
 static const UChar ellipsisUChar[] = { 0x2026, 0 };
 
-static Color parseColor(const JSON::Object* colorObject)
+// static
+Color InspectorDOMAgent::parseColor(const JSON::Object* colorObject)
 {
     if (!colorObject)
         return Color::transparent;
@@ -157,7 +164,7 @@ static Color parseConfigColor(const String& fieldName, const JSON::Object* confi
     RefPtr<JSON::Object> colorObject;
     configObject->getObject(fieldName, colorObject);
 
-    return parseColor(colorObject.get());
+    return InspectorDOMAgent::parseColor(colorObject.get());
 }
 
 static bool parseQuad(const JSON::Array& quadArray, FloatQuad* quad)
@@ -438,6 +445,20 @@ Node* InspectorDOMAgent::assertNode(ErrorString& errorString, int nodeId)
     return node;
 }
 
+Node* InspectorDOMAgent::assertNode(ErrorString& errorString, const int* nodeId, const String* objectId)
+{
+    Node* node = nullptr;
+    if (nodeId) {
+        node = assertNode(errorString, *nodeId);
+    } else if (objectId) {
+        node = nodeForObjectId(*objectId);
+        if (!node)
+            errorString = "Missing node for given objectId"_s;
+    } else
+        errorString = "Either nodeId or objectId must be specified"_s;
+    return node;
+}
+
 Document* InspectorDOMAgent::assertDocument(ErrorString& errorString, int nodeId)
 {
     Node* node = assertNode(errorString, nodeId);
@@ -1318,16 +1339,7 @@ void InspectorDOMAgent::highlightSelector(ErrorString& errorString, const JSON::
 
 void InspectorDOMAgent::highlightNode(ErrorString& errorString, const JSON::Object& highlightInspectorObject, const int* nodeId, const String* objectId)
 {
-    Node* node = nullptr;
-    if (nodeId)
-        node = assertNode(errorString, *nodeId);
-    else if (objectId) {
-        node = nodeForObjectId(*objectId);
-        if (!node)
-            errorString = "Missing node for given objectId"_s;
-    } else
-        errorString = "Either nodeId or objectId must be specified"_s;
-
+    Node* node = assertNode(errorString, nodeId, objectId);
     if (!node)
         return;
 
@@ -1475,18 +1487,77 @@ void InspectorDOMAgent::setInspectedNode(ErrorString& errorString, int nodeId)
     m_suppressEventListenerChangedEvent = false;
 }
 
-void InspectorDOMAgent::resolveNode(ErrorString& errorString, int nodeId, const String* objectGroup, RefPtr<Inspector::Protocol::Runtime::RemoteObject>& result)
+static FloatPoint contentsToRootView(FrameView& containingView, const FloatPoint& point)
 {
-    String objectGroupName = objectGroup ? *objectGroup : emptyString();
-    Node* node = assertNode(errorString, nodeId);
+    return containingView.convertToRootView(point - toFloatSize(containingView.documentScrollPositionRelativeToViewOrigin()));
+}
+
+static void frameQuadToViewport(FrameView& containingView, FloatQuad& quad)
+{
+    quad.setP1(contentsToRootView(containingView, quad.p1()));
+    quad.setP2(contentsToRootView(containingView, quad.p2()));
+    quad.setP3(contentsToRootView(containingView, quad.p3()));
+    quad.setP4(contentsToRootView(containingView, quad.p4()));
+}
+
+static RefPtr<Inspector::Protocol::DOM::Quad> buildObjectForQuad(const FloatQuad& quad)
+{
+    auto result = Inspector::Protocol::DOM::Quad::create();
+    result->addItem(quad.p1().x());
+    result->addItem(quad.p1().y());
+    result->addItem(quad.p2().x());
+    result->addItem(quad.p2().y());
+    result->addItem(quad.p3().x());
+    result->addItem(quad.p3().y());
+    result->addItem(quad.p4().x());
+    result->addItem(quad.p4().y());
+    return result;
+}
+
+static RefPtr<JSON::ArrayOf<Inspector::Protocol::DOM::Quad>> buildArrayOfQuads(const Vector<FloatQuad>& quads)
+{
+    auto result = JSON::ArrayOf<Inspector::Protocol::DOM::Quad>::create();
+    for (const auto& quad : quads)
+        result->addItem(buildObjectForQuad(quad));
+    return result;
+}
+
+void InspectorDOMAgent::getContentQuads(ErrorString& error, const String& objectId, RefPtr<JSON::ArrayOf<Inspector::Protocol::DOM::Quad>>& out_quads)
+{
+    Node* node = nodeForObjectId(objectId);
+    if (!node) {
+        error = "Node not found"_s;
+        return;
+    }
+    RenderObject* renderer = node->renderer();
+    if (!renderer) {
+        error = "Node doesn't have renderer"_s;
+        return;
+    }
+    Frame* containingFrame = renderer->document().frame();
+    FrameView* containingView = containingFrame ? containingFrame->view() : nullptr;
+    if (!containingView) {
+        error = "Internal error: no containing view"_s;
+        return;
+    }
+    Vector<FloatQuad> quads;
+    renderer->absoluteQuads(quads);
+    for (auto& quad : quads)
+        frameQuadToViewport(*containingView, quad);
+    out_quads = buildArrayOfQuads(quads);
+}
+
+void InspectorDOMAgent::resolveNode(ErrorString& errorString, const int* nodeId, const String* objectId, const int* contextId, const String* objectGroup, RefPtr<Inspector::Protocol::Runtime::RemoteObject>& result)
+{
+    Node* node = assertNode(errorString, nodeId, objectId);
     if (!node)
         return;
-    RefPtr<Inspector::Protocol::Runtime::RemoteObject> object = resolveNode(node, objectGroupName);
-    if (!object) {
+    String objectGroupName = objectGroup ? *objectGroup : emptyString();
+    result = resolveNode(node, objectGroupName, contextId);
+    if (!result) {
         errorString = "Missing injected script for given nodeId"_s;
         return;
     }
-    result = object;
 }
 
 void InspectorDOMAgent::getAttributes(ErrorString& errorString, int nodeId, RefPtr<JSON::ArrayOf<String>>& result)
@@ -2651,7 +2722,7 @@ void InspectorDOMAgent::pushNodeByPathToFrontend(ErrorString& errorString, const
         errorString = "Missing node for given path"_s;
 }
 
-RefPtr<Inspector::Protocol::Runtime::RemoteObject> InspectorDOMAgent::resolveNode(Node* node, const String& objectGroup)
+RefPtr<Inspector::Protocol::Runtime::RemoteObject> InspectorDOMAgent::resolveNode(Node* node, const String& objectGroup, const int* contextId)
 {
     Document* document = &node->document();
     if (auto* templateHost = document->templateDocumentHost())
@@ -2660,12 +2731,16 @@ RefPtr<Inspector::Protocol::Runtime::RemoteObject> InspectorDOMAgent::resolveNod
     if (!frame)
         return nullptr;
 
-    auto& state = *mainWorldExecState(frame);
-    auto injectedScript = m_injectedScriptManager.injectedScriptFor(&state);
+    InjectedScript injectedScript;
+    if (contextId) {
+        injectedScript = m_injectedScriptManager.injectedScriptForId(*contextId);
+    } else {
+        injectedScript = m_injectedScriptManager.injectedScriptFor(mainWorldExecState(frame));
+    }
     if (injectedScript.hasNoValue())
         return nullptr;
 
-    return injectedScript.wrapObject(nodeAsScriptValue(state, node), objectGroup);
+    return injectedScript.wrapObject(nodeAsScriptValue(*injectedScript.globalObject(), node), objectGroup);
 }
 
 Node* InspectorDOMAgent::scriptValueAsNode(JSC::JSValue value)
@@ -2686,4 +2761,46 @@ void InspectorDOMAgent::setAllowEditingUserAgentShadowTrees(ErrorString&, bool a
     m_allowEditingUserAgentShadowTrees = allow;
 }
 
+void InspectorDOMAgent::setInputFiles(ErrorString& errorString, const String& objectId, const JSON::Array& in_files) {
+    InjectedScript injectedScript = m_injectedScriptManager.injectedScriptForObjectId(objectId);
+    if (injectedScript.hasNoValue()) {
+        errorString = "Can not find element's context for given id"_s;
+        return;
+    }
+    Node* node = scriptValueAsNode(injectedScript.findObjectById(objectId));
+    if (!node) {
+        errorString = "Can not find element for given id"_s;
+        return;
+    }
+    if (node->nodeType() != Node::ELEMENT_NODE || node->nodeName() != "INPUT") {
+        errorString = "Not an input node"_s;
+        return;
+    }
+    HTMLInputElement* element = static_cast<HTMLInputElement*>(node);
+    Vector<Ref<File>> fileObjects;
+    for (unsigned i = 0; i < in_files.length(); ++i) {
+        RefPtr<JSON::Value> item = in_files.get(i);
+        RefPtr<JSON::Object> obj;
+        if (!item->asObject(obj)) {
+            errorString = "Invalid file payload format"_s;
+            return;
+        }
+        String name;
+        String type;
+        String data;
+        if (!obj->getString("name", name) || !obj->getString("type", type) || !obj->getString("data", data)) {
+            errorString = "Invalid file payload format"_s;
+            return;
+        }
+        Vector<uint8_t> buffer;
+        if (!base64Decode(data, buffer)) {
+            errorString = "Unable to decode given content"_s;
+            return;
+        }
+        fileObjects.append(File::create(Blob::create(SharedBuffer::create(WTFMove(buffer)), type), name));
+    }
+    RefPtr<FileList> fileList = FileList::create(WTFMove(fileObjects));
+    element->setFiles(WTFMove(fileList));
+}
+
 } // namespace WebCore
diff --git a/Source/WebCore/inspector/agents/InspectorDOMAgent.h b/Source/WebCore/inspector/agents/InspectorDOMAgent.h
index 51639abeb84..289792fe5ad 100644
--- a/Source/WebCore/inspector/agents/InspectorDOMAgent.h
+++ b/Source/WebCore/inspector/agents/InspectorDOMAgent.h
@@ -54,6 +54,7 @@ namespace WebCore {
 
 class AXCoreObject;
 class CharacterData;
+class Color;
 class DOMEditor;
 class Document;
 class Element;
@@ -88,6 +89,7 @@ public:
     static String toErrorString(Exception&&);
 
     static String documentURLString(Document*);
+    static Color parseColor(const JSON::Object*);
 
     // We represent embedded doms as a part of the same hierarchy. Hence we treat children of frame owners differently.
     // We also skip whitespace text nodes conditionally. Following methods encapsulate these specifics.
@@ -129,7 +131,7 @@ public:
     void performSearch(ErrorString&, const String& query, const JSON::Array* nodeIds, const bool* caseSensitive, String* searchId, int* resultCount) override;
     void getSearchResults(ErrorString&, const String& searchId, int fromIndex, int toIndex, RefPtr<JSON::ArrayOf<int>>&) override;
     void discardSearchResults(ErrorString&, const String& searchId) override;
-    void resolveNode(ErrorString&, int nodeId, const String* objectGroup, RefPtr<Inspector::Protocol::Runtime::RemoteObject>& result) override;
+    void resolveNode(ErrorString&, const int* nodeId, const String* objectId, const int* contextId, const String* objectGroup, RefPtr<Inspector::Protocol::Runtime::RemoteObject>& result) override;
     void getAttributes(ErrorString&, int nodeId, RefPtr<JSON::ArrayOf<String>>& result) override;
     void setInspectModeEnabled(ErrorString&, bool enabled, const JSON::Object* highlightConfig, const bool* showRulers) override;
     void requestNode(ErrorString&, const String& objectId, int* nodeId) override;
@@ -148,6 +150,8 @@ public:
     void focus(ErrorString&, int nodeId) override;
     void setInspectedNode(ErrorString&, int nodeId) override;
     void setAllowEditingUserAgentShadowTrees(ErrorString&, bool allow) final;
+    void getContentQuads(ErrorString&, const String& objectId, RefPtr<JSON::ArrayOf<Inspector::Protocol::DOM::Quad>>& out_quads) override;
+    void setInputFiles(ErrorString&, const String& objectId, const JSON::Array& in_files) override;
 
     // InspectorInstrumentation
     int identifierForNode(Node&);
@@ -183,7 +187,7 @@ public:
     Node* nodeForId(int nodeId);
     int boundNodeId(const Node*);
 
-    RefPtr<Inspector::Protocol::Runtime::RemoteObject> resolveNode(Node*, const String& objectGroup);
+    RefPtr<Inspector::Protocol::Runtime::RemoteObject> resolveNode(Node*, const String& objectGroup, const int* contextId);
     bool handleMousePress();
     void mouseDidMoveOverElement(const HitTestResult&, unsigned modifierFlags);
     void inspect(Node*);
@@ -194,6 +198,7 @@ public:
     void reset();
 
     Node* assertNode(ErrorString&, int nodeId);
+    Node* assertNode(ErrorString&, const int* nodeId, const String* objectId);
     Element* assertElement(ErrorString&, int nodeId);
     Document* assertDocument(ErrorString&, int nodeId);
 
diff --git a/Source/WebCore/inspector/agents/InspectorDOMStorageAgent.h b/Source/WebCore/inspector/agents/InspectorDOMStorageAgent.h
index b578660fbb3..a7c968bc9f8 100644
--- a/Source/WebCore/inspector/agents/InspectorDOMStorageAgent.h
+++ b/Source/WebCore/inspector/agents/InspectorDOMStorageAgent.h
@@ -40,6 +40,7 @@ class DOMStorageFrontendDispatcher;
 
 namespace WebCore {
 
+class Color;
 class Frame;
 class Page;
 class SecurityOrigin;
diff --git a/Source/WebCore/inspector/agents/InspectorPageAgent.cpp b/Source/WebCore/inspector/agents/InspectorPageAgent.cpp
index 01edd0060de..19d0b3acf2b 100644
--- a/Source/WebCore/inspector/agents/InspectorPageAgent.cpp
+++ b/Source/WebCore/inspector/agents/InspectorPageAgent.cpp
@@ -32,6 +32,8 @@
 #include "config.h"
 #include "InspectorPageAgent.h"
 
+#include "AXObjectCache.h"
+#include "BackForwardController.h"
 #include "CachedResource.h"
 #include "CachedResourceLoader.h"
 #include "Cookie.h"
@@ -39,12 +41,14 @@
 #include "CustomHeaderFields.h"
 #include "Document.h"
 #include "DocumentLoader.h"
+#include "FocusController.h"
 #include "Frame.h"
 #include "FrameLoadRequest.h"
 #include "FrameLoader.h"
 #include "FrameSnapshotting.h"
 #include "FrameView.h"
 #include "HTMLFrameOwnerElement.h"
+#include "HTMLInputElement.h"
 #include "HTMLNames.h"
 #include "ImageBuffer.h"
 #include "InspectorClient.h"
@@ -55,17 +59,21 @@
 #include "MIMETypeRegistry.h"
 #include "MemoryCache.h"
 #include "Page.h"
+#include "PageRuntimeAgent.h"
 #include "RenderObject.h"
 #include "RenderTheme.h"
 #include "ScriptController.h"
 #include "ScriptSourceCode.h"
+#include "ScriptState.h"
 #include "SecurityOrigin.h"
 #include "Settings.h"
 #include "StyleScope.h"
 #include "TextEncoding.h"
+#include "TypingCommand.h"
 #include "UserGestureIndicator.h"
 #include <JavaScriptCore/ContentSearchUtilities.h>
 #include <JavaScriptCore/IdentifiersFactory.h>
+#include <JavaScriptCore/InjectedScriptManager.h>
 #include <JavaScriptCore/RegularExpression.h>
 #include <wtf/ListHashSet.h>
 #include <wtf/Stopwatch.h>
@@ -337,6 +345,7 @@ InspectorPageAgent::InspectorPageAgent(PageAgentContext& context, InspectorClien
     , m_frontendDispatcher(makeUnique<Inspector::PageFrontendDispatcher>(context.frontendRouter))
     , m_backendDispatcher(Inspector::PageBackendDispatcher::create(context.backendDispatcher, this))
     , m_inspectedPage(context.inspectedPage)
+    , m_injectedScriptManager(context.injectedScriptManager)
     , m_client(client)
     , m_overlay(overlay)
 {
@@ -375,6 +384,8 @@ void InspectorPageAgent::enable(ErrorString& errorString)
 void InspectorPageAgent::disable(ErrorString&)
 {
     m_instrumentingAgents.setInspectorPageAgent(nullptr);
+    m_interceptFileChooserDialog = false;
+    m_bypassCSP = false;
 
     ErrorString unused;
     setShowPaintRects(unused, false);
@@ -382,6 +393,7 @@ void InspectorPageAgent::disable(ErrorString&)
     overrideUserAgent(unused, nullptr);
     setEmulatedMedia(unused, emptyString());
     setForcedAppearance(unused, emptyString());
+    m_isolatedWorldScripts.clear();
 
 #define DISABLE_INSPECTOR_OVERRIDE_SETTING(name) \
     m_inspectedPage.settings().set##name##InspectorOverride(WTF::nullopt);
@@ -412,14 +424,28 @@ void InspectorPageAgent::reload(ErrorString&, const bool* optionalReloadFromOrig
     m_inspectedPage.mainFrame().loader().reload(reloadOptions);
 }
 
-void InspectorPageAgent::navigate(ErrorString&, const String& url)
+void InspectorPageAgent::goBack(ErrorString& errorString)
+{
+    if (!m_inspectedPage.backForward().goBack())
+        errorString = "Failed to go back"_s;
+}
+
+void InspectorPageAgent::goForward(ErrorString& errorString)
+{
+    if (!m_inspectedPage.backForward().goForward())
+        errorString = "Failed to go forward"_s;
+}
+
+void InspectorPageAgent::navigate(ErrorString& errorString, const String& url, const String* frameId)
 {
     UserGestureIndicator indicator { ProcessingUserGesture };
-    Frame& frame = m_inspectedPage.mainFrame();
+    Frame* frame = frameId ? assertFrame(errorString, *frameId) : &m_inspectedPage.mainFrame();
+    if (!frame)
+        return;
 
-    ResourceRequest resourceRequest { frame.document()->completeURL(url) };
-    FrameLoadRequest frameLoadRequest { *frame.document(), frame.document()->securityOrigin(), resourceRequest, "_self"_s, LockHistory::No, LockBackForwardList::No, MaybeSendReferrer, AllowNavigationToInvalidURL::No, NewFrameOpenerPolicy::Allow, ShouldOpenExternalURLsPolicy::ShouldNotAllow, InitiatedByMainFrame::Unknown };
-    frame.loader().changeLocation(WTFMove(frameLoadRequest));
+    ResourceRequest resourceRequest { frame->document()->completeURL(url) };
+    FrameLoadRequest frameLoadRequest { *frame->document(), frame->document()->securityOrigin(), resourceRequest, "_self"_s, LockHistory::No, LockBackForwardList::No, MaybeSendReferrer, AllowNavigationToInvalidURL::No, NewFrameOpenerPolicy::Allow, ShouldOpenExternalURLsPolicy::ShouldNotAllow, InitiatedByMainFrame::Unknown };
+    frame->loader().changeLocation(WTFMove(frameLoadRequest));
 }
 
 void InspectorPageAgent::overrideUserAgent(ErrorString&, const String* value)
@@ -680,15 +706,16 @@ void InspectorPageAgent::setShowPaintRects(ErrorString&, bool show)
     m_overlay->setShowPaintRects(show);
 }
 
-void InspectorPageAgent::domContentEventFired()
+void InspectorPageAgent::domContentEventFired(Frame& frame)
 {
-    m_isFirstLayoutAfterOnLoad = true;
-    m_frontendDispatcher->domContentEventFired(timestamp());
+    if (frame.isMainFrame())
+        m_isFirstLayoutAfterOnLoad = true;
+    m_frontendDispatcher->domContentEventFired(timestamp(), frameId(&frame));
 }
 
-void InspectorPageAgent::loadEventFired()
+void InspectorPageAgent::loadEventFired(Frame& frame)
 {
-    m_frontendDispatcher->loadEventFired(timestamp());
+    m_frontendDispatcher->loadEventFired(timestamp(), frameId(&frame));
 }
 
 void InspectorPageAgent::frameNavigated(Frame& frame)
@@ -763,6 +790,12 @@ void InspectorPageAgent::frameClearedScheduledNavigation(Frame& frame)
     m_frontendDispatcher->frameClearedScheduledNavigation(frameId(&frame));
 }
 
+void InspectorPageAgent::didNavigateWithinPage(Frame& frame)
+{
+    String url = frame.document()->url().string();
+    m_frontendDispatcher->navigatedWithinDocument(frameId(&frame), url);
+}
+
 void InspectorPageAgent::defaultAppearanceDidChange(bool useDarkAppearance)
 {
     m_frontendDispatcher->defaultAppearanceDidChange(useDarkAppearance ? Inspector::Protocol::Page::Appearance::Dark : Inspector::Protocol::Page::Appearance::Light);
@@ -817,6 +850,38 @@ void InspectorPageAgent::didRecalculateStyle()
     m_overlay->update();
 }
 
+void InspectorPageAgent::runOpenPanel(HTMLInputElement* element, bool* intercept)
+{
+    if (m_interceptFileChooserDialog) {
+        *intercept = true;
+    } else {
+        return;
+    }
+    Document& document = element->document();
+    auto* frame =  document.frame();
+    if (!frame)
+        return;
+
+    auto& state = *mainWorldExecState(frame);
+    auto injectedScript = m_injectedScriptManager.injectedScriptFor(&state);
+    if (injectedScript.hasNoValue())
+        return;
+
+    m_frontendDispatcher->fileChooserOpened(frameId(frame), injectedScript.wrapObject(InspectorDOMAgent::nodeAsScriptValue(state, element), WTF::String()));
+}
+
+void InspectorPageAgent::frameAttached(Frame& frame)
+{
+    Frame* parent = frame.tree().parent();
+    String parentFrameId = frameId(parent);
+    m_frontendDispatcher->frameAttached(frameId(&frame), parent ? &parentFrameId : nullptr);
+}
+
+bool InspectorPageAgent::shouldBypassCSP()
+{
+    return m_bypassCSP;
+}
+
 Ref<Inspector::Protocol::Page::Frame> InspectorPageAgent::buildObjectForFrame(Frame* frame)
 {
     ASSERT_ARG(frame, frame);
@@ -988,4 +1053,491 @@ void InspectorPageAgent::archive(ErrorString& errorString, String* data)
 #endif
 }
 
+void InspectorPageAgent::insertText(ErrorString&, const String& text) {
+    UserGestureIndicator indicator { ProcessingUserGesture };
+    Document* focusedDocument = m_inspectedPage.focusController().focusedOrMainFrame().document();
+    TypingCommand::insertText(*focusedDocument, text, 0);
+}
+
+static String roleFromObject(RefPtr<AXCoreObject> axObject) {
+    String computedRoleString = axObject->computedRoleString();
+    if (!computedRoleString.isEmpty())
+        return computedRoleString;
+    AccessibilityRole role = axObject->roleValue();
+    switch(role) {
+        case AccessibilityRole::Annotation:
+            return "Annotation";
+        case AccessibilityRole::Application:
+            return "Application";
+        case AccessibilityRole::ApplicationAlert:
+            return "ApplicationAlert";
+        case AccessibilityRole::ApplicationAlertDialog:
+            return "ApplicationAlertDialog";
+        case AccessibilityRole::ApplicationDialog:
+            return "ApplicationDialog";
+        case AccessibilityRole::ApplicationGroup:
+            return "ApplicationGroup";
+        case AccessibilityRole::ApplicationLog:
+            return "ApplicationLog";
+        case AccessibilityRole::ApplicationMarquee:
+            return "ApplicationMarquee";
+        case AccessibilityRole::ApplicationStatus:
+            return "ApplicationStatus";
+        case AccessibilityRole::ApplicationTextGroup:
+            return "ApplicationTextGroup";
+        case AccessibilityRole::ApplicationTimer:
+            return "ApplicationTimer";
+        case AccessibilityRole::Audio:
+            return "Audio";
+        case AccessibilityRole::Blockquote:
+            return "Blockquote";
+        case AccessibilityRole::Browser:
+            return "Browser";
+        case AccessibilityRole::BusyIndicator:
+            return "BusyIndicator";
+        case AccessibilityRole::Button:
+            return "Button";
+        case AccessibilityRole::Canvas:
+            return "Canvas";
+        case AccessibilityRole::Caption:
+            return "Caption";
+        case AccessibilityRole::Cell:
+            return "Cell";
+        case AccessibilityRole::CheckBox:
+            return "CheckBox";
+        case AccessibilityRole::ColorWell:
+            return "ColorWell";
+        case AccessibilityRole::Column:
+            return "Column";
+        case AccessibilityRole::ColumnHeader:
+            return "ColumnHeader";
+        case AccessibilityRole::ComboBox:
+            return "ComboBox";
+        case AccessibilityRole::Definition:
+            return "Definition";
+        case AccessibilityRole::Deletion:
+            return "Deletion";
+        case AccessibilityRole::DescriptionList:
+            return "DescriptionList";
+        case AccessibilityRole::DescriptionListTerm:
+            return "DescriptionListTerm";
+        case AccessibilityRole::DescriptionListDetail:
+            return "DescriptionListDetail";
+        case AccessibilityRole::Details:
+            return "Details";
+        case AccessibilityRole::Directory:
+            return "Directory";
+        case AccessibilityRole::DisclosureTriangle:
+            return "DisclosureTriangle";
+        case AccessibilityRole::Div:
+            return "Div";
+        case AccessibilityRole::Document:
+            return "Document";
+        case AccessibilityRole::DocumentArticle:
+            return "DocumentArticle";
+        case AccessibilityRole::DocumentMath:
+            return "DocumentMath";
+        case AccessibilityRole::DocumentNote:
+            return "DocumentNote";
+        case AccessibilityRole::Drawer:
+            return "Drawer";
+        case AccessibilityRole::EditableText:
+            return "EditableText";
+        case AccessibilityRole::Feed:
+            return "Feed";
+        case AccessibilityRole::Figure:
+            return "Figure";
+        case AccessibilityRole::Footer:
+            return "Footer";
+        case AccessibilityRole::Footnote:
+            return "Footnote";
+        case AccessibilityRole::Form:
+            return "Form";
+        case AccessibilityRole::GraphicsDocument:
+            return "GraphicsDocument";
+        case AccessibilityRole::GraphicsObject:
+            return "GraphicsObject";
+        case AccessibilityRole::GraphicsSymbol:
+            return "GraphicsSymbol";
+        case AccessibilityRole::Grid:
+            return "Grid";
+        case AccessibilityRole::GridCell:
+            return "GridCell";
+        case AccessibilityRole::Group:
+            return "Group";
+        case AccessibilityRole::GrowArea:
+            return "GrowArea";
+        case AccessibilityRole::Heading:
+            return "Heading";
+        case AccessibilityRole::HelpTag:
+            return "HelpTag";
+        case AccessibilityRole::HorizontalRule:
+            return "HorizontalRule";
+        case AccessibilityRole::Ignored:
+            return "Ignored";
+        case AccessibilityRole::Inline:
+            return "Inline";
+        case AccessibilityRole::Image:
+            return "Image";
+        case AccessibilityRole::ImageMap:
+            return "ImageMap";
+        case AccessibilityRole::ImageMapLink:
+            return "ImageMapLink";
+        case AccessibilityRole::Incrementor:
+            return "Incrementor";
+        case AccessibilityRole::Insertion:
+            return "Insertion";
+        case AccessibilityRole::Label:
+            return "Label";
+        case AccessibilityRole::LandmarkBanner:
+            return "LandmarkBanner";
+        case AccessibilityRole::LandmarkComplementary:
+            return "LandmarkComplementary";
+        case AccessibilityRole::LandmarkContentInfo:
+            return "LandmarkContentInfo";
+        case AccessibilityRole::LandmarkDocRegion:
+            return "LandmarkDocRegion";
+        case AccessibilityRole::LandmarkMain:
+            return "LandmarkMain";
+        case AccessibilityRole::LandmarkNavigation:
+            return "LandmarkNavigation";
+        case AccessibilityRole::LandmarkRegion:
+            return "LandmarkRegion";
+        case AccessibilityRole::LandmarkSearch:
+            return "LandmarkSearch";
+        case AccessibilityRole::Legend:
+            return "Legend";
+        case AccessibilityRole::Link:
+            return "Link";
+        case AccessibilityRole::List:
+            return "List";
+        case AccessibilityRole::ListBox:
+            return "ListBox";
+        case AccessibilityRole::ListBoxOption:
+            return "ListBoxOption";
+        case AccessibilityRole::ListItem:
+            return "ListItem";
+        case AccessibilityRole::ListMarker:
+            return "ListMarker";
+        case AccessibilityRole::Mark:
+            return "Mark";
+        case AccessibilityRole::MathElement:
+            return "MathElement";
+        case AccessibilityRole::Matte:
+            return "Matte";
+        case AccessibilityRole::Menu:
+            return "Menu";
+        case AccessibilityRole::MenuBar:
+            return "MenuBar";
+        case AccessibilityRole::MenuButton:
+            return "MenuButton";
+        case AccessibilityRole::MenuItem:
+            return "MenuItem";
+        case AccessibilityRole::MenuItemCheckbox:
+            return "MenuItemCheckbox";
+        case AccessibilityRole::MenuItemRadio:
+            return "MenuItemRadio";
+        case AccessibilityRole::MenuListPopup:
+            return "MenuListPopup";
+        case AccessibilityRole::MenuListOption:
+            return "MenuListOption";
+        case AccessibilityRole::Meter:
+            return "Meter";
+        case AccessibilityRole::Outline:
+            return "Outline";
+        case AccessibilityRole::Paragraph:
+            return "Paragraph";
+        case AccessibilityRole::PopUpButton:
+            return "PopUpButton";
+        case AccessibilityRole::Pre:
+            return "Pre";
+        case AccessibilityRole::Presentational:
+            return "Presentational";
+        case AccessibilityRole::ProgressIndicator:
+            return "ProgressIndicator";
+        case AccessibilityRole::RadioButton:
+            return "RadioButton";
+        case AccessibilityRole::RadioGroup:
+            return "RadioGroup";
+        case AccessibilityRole::RowHeader:
+            return "RowHeader";
+        case AccessibilityRole::Row:
+            return "Row";
+        case AccessibilityRole::RowGroup:
+            return "RowGroup";
+        case AccessibilityRole::RubyBase:
+            return "RubyBase";
+        case AccessibilityRole::RubyBlock:
+            return "RubyBlock";
+        case AccessibilityRole::RubyInline:
+            return "RubyInline";
+        case AccessibilityRole::RubyRun:
+            return "RubyRun";
+        case AccessibilityRole::RubyText:
+            return "RubyText";
+        case AccessibilityRole::Ruler:
+            return "Ruler";
+        case AccessibilityRole::RulerMarker:
+            return "RulerMarker";
+        case AccessibilityRole::ScrollArea:
+            return "ScrollArea";
+        case AccessibilityRole::ScrollBar:
+            return "ScrollBar";
+        case AccessibilityRole::SearchField:
+            return "SearchField";
+        case AccessibilityRole::Sheet:
+            return "Sheet";
+        case AccessibilityRole::Slider:
+            return "Slider";
+        case AccessibilityRole::SliderThumb:
+            return "SliderThumb";
+        case AccessibilityRole::SpinButton:
+            return "SpinButton";
+        case AccessibilityRole::SpinButtonPart:
+            return "SpinButtonPart";
+        case AccessibilityRole::SplitGroup:
+            return "SplitGroup";
+        case AccessibilityRole::Splitter:
+            return "Splitter";
+        case AccessibilityRole::StaticText:
+            return "StaticText";
+        case AccessibilityRole::Subscript:
+            return "Subscript";
+        case AccessibilityRole::Summary:
+            return "Summary";
+        case AccessibilityRole::Superscript:
+            return "Superscript";
+        case AccessibilityRole::Switch:
+            return "Switch";
+        case AccessibilityRole::SystemWide:
+            return "SystemWide";
+        case AccessibilityRole::SVGRoot:
+            return "SVGRoot";
+        case AccessibilityRole::SVGText:
+            return "SVGText";
+        case AccessibilityRole::SVGTSpan:
+            return "SVGTSpan";
+        case AccessibilityRole::SVGTextPath:
+            return "SVGTextPath";
+        case AccessibilityRole::TabGroup:
+            return "TabGroup";
+        case AccessibilityRole::TabList:
+            return "TabList";
+        case AccessibilityRole::TabPanel:
+            return "TabPanel";
+        case AccessibilityRole::Tab:
+            return "Tab";
+        case AccessibilityRole::Table:
+            return "Table";
+        case AccessibilityRole::TableHeaderContainer:
+            return "TableHeaderContainer";
+        case AccessibilityRole::TextArea:
+            return "TextArea";
+        case AccessibilityRole::TextGroup:
+            return "TextGroup";
+        case AccessibilityRole::Term:
+            return "Term";
+        case AccessibilityRole::Time:
+            return "Time";
+        case AccessibilityRole::Tree:
+            return "Tree";
+        case AccessibilityRole::TreeGrid:
+            return "TreeGrid";
+        case AccessibilityRole::TreeItem:
+            return "TreeItem";
+        case AccessibilityRole::TextField:
+            return "TextField";
+        case AccessibilityRole::ToggleButton:
+            return "ToggleButton";
+        case AccessibilityRole::Toolbar:
+            return "Toolbar";
+        case AccessibilityRole::Unknown:
+            return "Unknown";
+        case AccessibilityRole::UserInterfaceTooltip:
+            return "UserInterfaceTooltip";
+        case AccessibilityRole::ValueIndicator:
+            return "ValueIndicator";
+        case AccessibilityRole::Video:
+            return "Video";
+        case AccessibilityRole::WebApplication:
+            return "WebApplication";
+        case AccessibilityRole::WebArea:
+            return "WebArea";
+        case AccessibilityRole::WebCoreLink:
+            return "WebCoreLink";
+        case AccessibilityRole::Window:
+            return "Window";
+    };
+    return "Unknown";
+}
+
+static RefPtr<Inspector::Protocol::Page::AXNode> snapshotForAXObject(RefPtr<AXCoreObject> axObject) {
+    auto axNode = Inspector::Protocol::Page::AXNode::create()
+        .setRole(roleFromObject(axObject))
+        .release();
+
+    if (!axObject->computedLabel().isEmpty())
+        axNode->setName(axObject->computedLabel());
+    if (!axObject->stringValue().isEmpty())
+        axNode->setValue(JSON::Value::create(axObject->stringValue()));
+    if (!axObject->accessibilityDescription().isEmpty())
+        axNode->setDescription(axObject->accessibilityDescription());
+    if (!axObject->keyShortcutsValue().isEmpty())
+        axNode->setKeyshortcuts(axObject->keyShortcutsValue());
+    if (!axObject->valueDescription().isEmpty())
+        axNode->setValuetext(axObject->valueDescription());
+    if (!axObject->isEnabled())
+        axNode->setDisabled(!axObject->isEnabled());
+    if (axObject->supportsExpanded())
+        axNode->setExpanded(axObject->isExpanded());
+    if (axObject->isFocused())
+        axNode->setFocused(axObject->isFocused());
+    if (axObject->isModalNode())
+        axNode->setModal(axObject->isModalNode());
+    bool multiline = axObject->ariaIsMultiline() || axObject->roleValue() == AccessibilityRole::TextArea;
+    if (multiline)
+        axNode->setMultiline(multiline);
+    if (axObject->isMultiSelectable())
+        axNode->setMultiselectable(axObject->isMultiSelectable());
+    if (axObject->supportsReadOnly())
+        axNode->setReadonly(axObject->readOnlyValue() != "false");
+    if (axObject->supportsRequiredAttribute())
+        axNode->setRequired(axObject->isRequired());
+    if (axObject->isSelected())
+        axNode->setSelected(axObject->isSelected());
+    if (axObject->supportsChecked()) {
+        AccessibilityButtonState checkedState = axObject->checkboxOrRadioValue();
+        switch (checkedState) {
+            case AccessibilityButtonState::On:
+                axNode->setChecked(Inspector::Protocol::Page::AXNode::Checked::True);
+                break;
+            case AccessibilityButtonState::Off:
+                axNode->setChecked(Inspector::Protocol::Page::AXNode::Checked::False);
+                break;
+            case AccessibilityButtonState::Mixed:
+                axNode->setChecked(Inspector::Protocol::Page::AXNode::Checked::Mixed);
+                break;
+        }
+    }
+    if (axObject->supportsPressed()) {
+        AccessibilityButtonState checkedState = axObject->checkboxOrRadioValue();
+        switch (checkedState) {
+            case AccessibilityButtonState::On:
+                axNode->setPressed(Inspector::Protocol::Page::AXNode::Pressed::True);
+                break;
+            case AccessibilityButtonState::Off:
+                axNode->setPressed(Inspector::Protocol::Page::AXNode::Pressed::False);
+                break;
+            case AccessibilityButtonState::Mixed:
+                axNode->setPressed(Inspector::Protocol::Page::AXNode::Pressed::Mixed);
+                break;
+        }
+    }
+    unsigned level = axObject->hierarchicalLevel() ? axObject->hierarchicalLevel() : axObject->headingLevel();
+    if (level)
+        axNode->setLevel(level);
+    if (axObject->minValueForRange() != 0)
+        axNode->setValuemin(axObject->minValueForRange());
+    if (axObject->maxValueForRange() != 0)
+        axNode->setValuemax(axObject->maxValueForRange());
+    if (axObject->supportsAutoComplete())
+        axNode->setAutocomplete(axObject->autoCompleteValue());
+    if (axObject->hasPopup())
+        axNode->setHaspopup(axObject->popupValue());
+
+    String invalidValue = axObject->invalidStatus();
+    if (invalidValue != "false") {
+        if (invalidValue == "grammar")
+            axNode->setInvalid(Inspector::Protocol::Page::AXNode::Invalid::Grammar);
+        else if (invalidValue == "spelling")
+            axNode->setInvalid(Inspector::Protocol::Page::AXNode::Invalid::Spelling);
+        else // Future versions of ARIA may allow additional truthy values. Ex. format, order, or size.
+            axNode->setInvalid(Inspector::Protocol::Page::AXNode::Invalid::True);
+    }
+    switch (axObject->orientation()) {
+        case AccessibilityOrientation::Undefined:
+            break;
+        case AccessibilityOrientation::Vertical:
+            axNode->setOrientation("vertical"_s);
+            break;
+        case AccessibilityOrientation::Horizontal:
+            axNode->setOrientation("horizontal"_s);
+            break;
+    }
+
+    if (axObject->isKeyboardFocusable())
+        axNode->setFocusable(axObject->isKeyboardFocusable());
+
+    if (axObject->hasChildren()) {
+        RefPtr<JSON::ArrayOf<Inspector::Protocol::Page::AXNode>> children = JSON::ArrayOf<Inspector::Protocol::Page::AXNode>::create();
+        for (auto& childObject : axObject->children())
+            children->addItem(snapshotForAXObject(childObject));
+        axNode->setChildren(children);
+    }
+    return axNode;
+}
+
+
+void InspectorPageAgent::accessibilitySnapshot(ErrorString& errorString, RefPtr<Inspector::Protocol::Page::AXNode>& out_axNode) {
+    if (!WebCore::AXObjectCache::accessibilityEnabled())
+        WebCore::AXObjectCache::enableAccessibility();
+    auto document = makeRefPtr(m_inspectedPage.mainFrame().document());
+    if (!document) {
+        errorString = "No document for main frame"_s;
+        return;
+    }
+    AXObjectCache* axObjectCache = document->axObjectCache();
+    if (!axObjectCache) {
+        errorString = "No AXObjectCache for main document"_s;
+        return;
+    }
+    AXCoreObject* axObject = axObjectCache->rootObject();
+    if (!axObject) {
+        errorString = "No AXObject for main document"_s;
+        return;
+    }
+
+    out_axNode = snapshotForAXObject(makeRefPtr(axObject));
+}
+
+void InspectorPageAgent::setInterceptFileChooserDialog(ErrorString&, bool enabled) {
+    m_interceptFileChooserDialog = enabled;
+}
+
+void InspectorPageAgent::setDefaultBackgroundColorOverride(ErrorString& errorString, const JSON::Object* color)
+{
+    FrameView* view = m_inspectedPage.mainFrame().view();
+    if (!view) {
+        errorString = "Internal error: No frame view to set color two"_s;
+        return;
+    }
+    if (!color) {
+        view->updateBackgroundRecursively(Optional<Color>());
+        return;
+    }
+    view->updateBackgroundRecursively(InspectorDOMAgent::parseColor(color));
+}
+
+void InspectorPageAgent::createIsolatedWorld(ErrorString& errorString, const String& name, const String* optionalSource) {
+    if (m_isolatedWorldScripts.find(name) != m_isolatedWorldScripts.end()) {
+        errorString = "World with the given name already exists"_s;
+        return;
+    }
+    auto* pageRuntimeAgent = m_instrumentingAgents.pageRuntimeAgent();
+    if (!pageRuntimeAgent) {
+        errorString = "Runtime agent must be enabled"_s;
+        return;
+    }
+
+    String source = optionalSource ? *optionalSource : String();
+    m_isolatedWorldScripts.set(name, source);
+
+    for (Frame* frame = &m_inspectedPage.mainFrame(); frame; frame = frame->tree().traverseNext())
+        pageRuntimeAgent->createIsolatedWorld(*frame, name, source);
+}
+
+void InspectorPageAgent::setBypassCSP(ErrorString&, bool enabled) {
+    m_bypassCSP = enabled;
+}
+
 } // namespace WebCore
diff --git a/Source/WebCore/inspector/agents/InspectorPageAgent.h b/Source/WebCore/inspector/agents/InspectorPageAgent.h
index 4fd8c0b1016..9954be9e35a 100644
--- a/Source/WebCore/inspector/agents/InspectorPageAgent.h
+++ b/Source/WebCore/inspector/agents/InspectorPageAgent.h
@@ -40,10 +40,15 @@
 #include <wtf/Seconds.h>
 #include <wtf/text/WTFString.h>
 
+namespace Inspector {
+class InjectedScriptManager;
+}
+
 namespace WebCore {
 
 class DocumentLoader;
 class Frame;
+class HTMLInputElement;
 class InspectorClient;
 class InspectorOverlay;
 class Page;
@@ -96,7 +101,9 @@ public:
     void enable(ErrorString&) override;
     void disable(ErrorString&) override;
     void reload(ErrorString&, const bool* optionalReloadFromOrigin, const bool* optionalRevalidateAllResources) override;
-    void navigate(ErrorString&, const String& url) override;
+    void goBack(ErrorString&) override;
+    void goForward(ErrorString&) override;
+    void navigate(ErrorString&, const String& url, const String* frameId) override;
     void overrideUserAgent(ErrorString&, const String* value) override;
     void overrideSetting(ErrorString&, const String& setting, const bool* value) override;
     void getCookies(ErrorString&, RefPtr<JSON::ArrayOf<Inspector::Protocol::Page::Cookie>>& cookies) override;
@@ -113,12 +120,18 @@ public:
     void getCompositingBordersVisible(ErrorString&, bool* out_param) override;
     void setCompositingBordersVisible(ErrorString&, bool) override;
     void snapshotNode(ErrorString&, int nodeId, String* outDataURL) override;
-    void snapshotRect(ErrorString&, int x, int y, int width, int height, const String& coordinateSystem, String* outDataURL) override;
+    void snapshotRect(ErrorString&, int x, int y, int width,  int height, const String& coordinateSystem, String* outDataURL) override;
     void archive(ErrorString&, String* data) override;
+    void insertText(ErrorString&, const String& text) override;
+    void accessibilitySnapshot(ErrorString&, RefPtr<Inspector::Protocol::Page::AXNode>& out_axNode) override;
+    void setInterceptFileChooserDialog(ErrorString&, bool enabled) override;
+    void setDefaultBackgroundColorOverride(ErrorString&, const JSON::Object*) override;
+    void createIsolatedWorld(ErrorString&, const String&, const String*) override;
+    void setBypassCSP(ErrorString&, bool) override;
 
     // InspectorInstrumentation
-    void domContentEventFired();
-    void loadEventFired();
+    void domContentEventFired(Frame&);
+    void loadEventFired(Frame&);
     void frameNavigated(Frame&);
     void frameDetached(Frame&);
     void loaderDetachedFromFrame(DocumentLoader&);
@@ -126,6 +139,7 @@ public:
     void frameStoppedLoading(Frame&);
     void frameScheduledNavigation(Frame&, Seconds delay);
     void frameClearedScheduledNavigation(Frame&);
+    void didNavigateWithinPage(Frame&);
     void defaultAppearanceDidChange(bool useDarkAppearance);
     void applyUserAgentOverride(String&);
     void applyEmulatedMedia(String&);
@@ -134,11 +148,15 @@ public:
     void didLayout();
     void didScroll();
     void didRecalculateStyle();
+    void runOpenPanel(HTMLInputElement* element, bool* intercept);
+    void frameAttached(Frame&);
+    bool shouldBypassCSP();
 
     Frame* frameForId(const String& frameId);
     WEBCORE_EXPORT String frameId(Frame*);
     String loaderId(DocumentLoader*);
     Frame* assertFrame(ErrorString&, const String& frameId);
+    HashMap<String, String> isolatedWorldScripts() { return m_isolatedWorldScripts; };
 
 private:
     double timestamp();
@@ -153,6 +171,7 @@ private:
     RefPtr<Inspector::PageBackendDispatcher> m_backendDispatcher;
 
     Page& m_inspectedPage;
+    Inspector::InjectedScriptManager& m_injectedScriptManager;
     InspectorClient* m_client { nullptr };
     InspectorOverlay* m_overlay { nullptr };
 
@@ -163,8 +182,11 @@ private:
     String m_emulatedMedia;
     String m_forcedAppearance;
     String m_bootstrapScript;
+    HashMap<String, String> m_isolatedWorldScripts;
     bool m_isFirstLayoutAfterOnLoad { false };
     bool m_showPaintRects { false };
+    bool m_interceptFileChooserDialog { false };
+    bool m_bypassCSP { false };
 };
 
 } // namespace WebCore
diff --git a/Source/WebCore/inspector/agents/page/PageRuntimeAgent.cpp b/Source/WebCore/inspector/agents/page/PageRuntimeAgent.cpp
index b4b9d5cd9b1..e26ed4d2c23 100644
--- a/Source/WebCore/inspector/agents/page/PageRuntimeAgent.cpp
+++ b/Source/WebCore/inspector/agents/page/PageRuntimeAgent.cpp
@@ -40,6 +40,7 @@
 #include "Page.h"
 #include "PageConsoleClient.h"
 #include "ScriptController.h"
+#include "ScriptSourceCode.h"
 #include "ScriptState.h"
 #include "SecurityOrigin.h"
 #include "UserGestureEmulationScope.h"
@@ -70,14 +71,12 @@ PageRuntimeAgent::~PageRuntimeAgent() = default;
 
 void PageRuntimeAgent::enable(ErrorString& errorString)
 {
-    bool enabled = m_instrumentingAgents.pageRuntimeAgent() == this;
+    if (m_instrumentingAgents.pageRuntimeAgent() == this)
+        return;
+    reportExecutionContextCreation();
 
     InspectorRuntimeAgent::enable(errorString);
-
     m_instrumentingAgents.setPageRuntimeAgent(this);
-
-    if (!enabled)
-        reportExecutionContextCreation();
 }
 
 void PageRuntimeAgent::disable(ErrorString& errorString)
@@ -99,9 +98,15 @@ void PageRuntimeAgent::didClearWindowObjectInWorld(Frame& frame)
     if (!pageAgent)
         return;
 
-    auto frameId = pageAgent->frameId(&frame);
+    // Force main world creation.
     auto* scriptState = mainWorldExecState(&frame);
-    notifyContextCreated(frameId, scriptState, nullptr, true);
+    Document* document = frame.document();
+    String worldName = document ? document->securityOrigin().toRawString() : String();
+    notifyContextCreated(frame, scriptState, worldName, true);
+
+    // Create user worlds.
+    for (auto pair : pageAgent->isolatedWorldScripts())
+        createIsolatedWorld(frame, pair.key, pair.value);
 }
 
 InjectedScript PageRuntimeAgent::injectedScriptForEval(ErrorString& errorString, const int* executionContextId)
@@ -138,36 +143,38 @@ void PageRuntimeAgent::reportExecutionContextCreation()
 
     Vector<std::pair<JSC::JSGlobalObject*, SecurityOrigin*>> isolatedContexts;
     for (Frame* frame = &m_inspectedPage.mainFrame(); frame; frame = frame->tree().traverseNext()) {
-        if (!frame->script().canExecuteScripts(NotAboutToExecuteScript))
-            continue;
-
-        String frameId = pageAgent->frameId(frame);
-
         JSC::JSGlobalObject* scriptState = mainWorldExecState(frame);
-        notifyContextCreated(frameId, scriptState, nullptr, true);
+        Document* document = frame->document();
+        String worldName = document ? document->securityOrigin().toRawString() : String();
+        notifyContextCreated(*frame, scriptState, worldName, true);
         frame->script().collectIsolatedContexts(isolatedContexts);
         if (isolatedContexts.isEmpty())
             continue;
-        for (auto& context : isolatedContexts)
-            notifyContextCreated(frameId, context.first, context.second, false);
+        for (auto& context : isolatedContexts) {
+            if (scriptState == context.first)
+                continue;
+            String name = context.second ? context.second->toRawString() : String();
+            notifyContextCreated(*frame, context.first, name, false);
+        }
         isolatedContexts.clear();
     }
 }
 
-void PageRuntimeAgent::notifyContextCreated(const String& frameId, JSC::JSGlobalObject* scriptState, SecurityOrigin* securityOrigin, bool isPageContext)
+void PageRuntimeAgent::notifyContextCreated(Frame& frame, JSC::JSGlobalObject* scriptState, const String& contextName, bool isPageContext)
 {
-    ASSERT(securityOrigin || isPageContext);
-
+    auto* pageAgent = m_instrumentingAgents.inspectorPageAgent();
+    if (!pageAgent)
+        return;
+    String frameId = pageAgent->frameId(&frame);
     InjectedScript result = injectedScriptManager().injectedScriptFor(scriptState);
     if (result.hasNoValue())
         return;
 
     int executionContextId = injectedScriptManager().injectedScriptIdFor(scriptState);
-    String name = securityOrigin ? securityOrigin->toRawString() : String();
     m_frontendDispatcher->executionContextCreated(ExecutionContextDescription::create()
         .setId(executionContextId)
         .setIsPageContext(isPageContext)
-        .setName(name)
+        .setName(contextName)
         .setFrameId(frameId)
         .release());
 }
@@ -184,4 +191,13 @@ void PageRuntimeAgent::callFunctionOn(ErrorString& errorString, const String& ob
     InspectorRuntimeAgent::callFunctionOn(errorString, objectId, expression, optionalArguments, doNotPauseOnExceptionsAndMuteConsole, returnByValue, generatePreview, emulateUserGesture, result, wasThrown);
 }
 
+void PageRuntimeAgent::createIsolatedWorld(Frame& frame, const String& name, const String& source) {
+    Ref<DOMWrapperWorld> world = ScriptController::createWorld();
+    frame.windowProxy().jsWindowProxy(world)->window();
+    if (!source.isEmpty())
+        frame.script().evaluateInWorld(ScriptSourceCode(source, URL { URL(), "web-inspector://isolate_world.js"_s }), world);
+    auto* scriptState = frame.windowProxy().jsWindowProxy(world)->window();
+    notifyContextCreated(frame, scriptState, name, false);
+}
+
 } // namespace WebCore
diff --git a/Source/WebCore/inspector/agents/page/PageRuntimeAgent.h b/Source/WebCore/inspector/agents/page/PageRuntimeAgent.h
index 54a00e05828..82189bf260d 100644
--- a/Source/WebCore/inspector/agents/page/PageRuntimeAgent.h
+++ b/Source/WebCore/inspector/agents/page/PageRuntimeAgent.h
@@ -63,16 +63,17 @@ public:
     void frameNavigated(Frame&);
     void didClearWindowObjectInWorld(Frame&);
 
+    void createIsolatedWorld(Frame& frame, const String& name, const String& source);
+
 private:
     Inspector::InjectedScript injectedScriptForEval(ErrorString&, const int* executionContextId) override;
     void muteConsole() override;
     void unmuteConsole() override;
     void reportExecutionContextCreation();
-    void notifyContextCreated(const String& frameId, JSC::JSGlobalObject*, SecurityOrigin*, bool isPageContext);
+    void notifyContextCreated(Frame&, JSC::JSGlobalObject*, const String&, bool isPageContext);
 
     std::unique_ptr<Inspector::RuntimeFrontendDispatcher> m_frontendDispatcher;
     RefPtr<Inspector::RuntimeBackendDispatcher> m_backendDispatcher;
-
     InstrumentingAgents& m_instrumentingAgents;
 
     Page& m_inspectedPage;
diff --git a/Source/WebCore/loader/FrameLoader.cpp b/Source/WebCore/loader/FrameLoader.cpp
index 0f1f281a594..db269b0ad45 100644
--- a/Source/WebCore/loader/FrameLoader.cpp
+++ b/Source/WebCore/loader/FrameLoader.cpp
@@ -1203,6 +1203,7 @@ void FrameLoader::loadInSameDocument(const URL& url, SerializedScriptValue* stat
     }
 
     m_client.dispatchDidNavigateWithinPage();
+    InspectorInstrumentation::didNavigateWithinPage(m_frame);
 
     m_frame.document()->statePopped(stateObject ? Ref<SerializedScriptValue> { *stateObject } : SerializedScriptValue::nullValue());
     m_client.dispatchDidPopStateWithinPage();
@@ -3971,9 +3972,6 @@ String FrameLoader::referrer() const
 
 void FrameLoader::dispatchDidClearWindowObjectsInAllWorlds()
 {
-    if (!m_frame.script().canExecuteScripts(NotAboutToExecuteScript))
-        return;
-
     Vector<Ref<DOMWrapperWorld>> worlds;
     ScriptController::getAllWorlds(worlds);
     for (auto& world : worlds)
@@ -3982,13 +3980,12 @@ void FrameLoader::dispatchDidClearWindowObjectsInAllWorlds()
 
 void FrameLoader::dispatchDidClearWindowObjectInWorld(DOMWrapperWorld& world)
 {
-    if (!m_frame.script().canExecuteScripts(NotAboutToExecuteScript) || !m_frame.windowProxy().existingJSWindowProxy(world))
-        return;
+    if (m_frame.script().canExecuteScripts(NotAboutToExecuteScript) && m_frame.windowProxy().existingJSWindowProxy(world)) {
+        m_client.dispatchDidClearWindowObjectInWorld(world);
 
-    m_client.dispatchDidClearWindowObjectInWorld(world);
-
-    if (Page* page = m_frame.page())
-        page->inspectorController().didClearWindowObjectInWorld(m_frame, world);
+        if (Page* page = m_frame.page())
+            page->inspectorController().didClearWindowObjectInWorld(m_frame, world);
+    }
 
     InspectorInstrumentation::didClearWindowObjectInWorld(m_frame, world);
 }
diff --git a/Source/WebCore/page/Frame.cpp b/Source/WebCore/page/Frame.cpp
index 22cc1fd15bc..4b0e232a19c 100644
--- a/Source/WebCore/page/Frame.cpp
+++ b/Source/WebCore/page/Frame.cpp
@@ -180,6 +180,7 @@ Frame::Frame(Page& page, HTMLFrameOwnerElement* ownerElement, FrameLoaderClient&
 void Frame::init()
 {
     m_loader->init();
+    InspectorInstrumentation::frameAttached(this);
 }
 
 Ref<Frame> Frame::create(Page* page, HTMLFrameOwnerElement* ownerElement, FrameLoaderClient* client)
diff --git a/Source/WebCore/page/History.cpp b/Source/WebCore/page/History.cpp
index 9c58b06f4c4..3d624733c36 100644
--- a/Source/WebCore/page/History.cpp
+++ b/Source/WebCore/page/History.cpp
@@ -259,6 +259,7 @@ ExceptionOr<void> History::stateObjectAdded(RefPtr<SerializedScriptValue>&& data
 
     if (!urlString.isEmpty())
         frame->document()->updateURLForPushOrReplaceState(fullURL);
+    InspectorInstrumentation::didNavigateWithinPage(*frame);
 
     if (stateObjectType == StateObjectType::Push) {
         frame->loader().history().pushState(WTFMove(data), title, fullURL.string());
diff --git a/Source/WebCore/page/csp/ContentSecurityPolicy.cpp b/Source/WebCore/page/csp/ContentSecurityPolicy.cpp
index ad6f5209c52..0fcf4fe9877 100644
--- a/Source/WebCore/page/csp/ContentSecurityPolicy.cpp
+++ b/Source/WebCore/page/csp/ContentSecurityPolicy.cpp
@@ -298,6 +298,8 @@ bool ContentSecurityPolicy::protocolMatchesSelf(const URL& url) const
 template<typename Predicate, typename... Args>
 typename std::enable_if<!std::is_convertible<Predicate, ContentSecurityPolicy::ViolatedDirectiveCallback>::value, bool>::type ContentSecurityPolicy::allPoliciesWithDispositionAllow(Disposition disposition, Predicate&& predicate, Args&&... args) const
 {
+    if (InspectorInstrumentation::shouldBypassCSP(m_scriptExecutionContext))
+        return true;
     bool isReportOnly = disposition == ContentSecurityPolicy::Disposition::ReportOnly;
     for (auto& policy : m_policies) {
         if (policy->isReportOnly() != isReportOnly)
@@ -311,6 +313,8 @@ typename std::enable_if<!std::is_convertible<Predicate, ContentSecurityPolicy::V
 template<typename Predicate, typename... Args>
 bool ContentSecurityPolicy::allPoliciesWithDispositionAllow(Disposition disposition, ViolatedDirectiveCallback&& callback, Predicate&& predicate, Args&&... args) const
 {
+    if (InspectorInstrumentation::shouldBypassCSP(m_scriptExecutionContext))
+        return true;
     bool isReportOnly = disposition == ContentSecurityPolicy::Disposition::ReportOnly;
     bool isAllowed = true;
     for (auto& policy : m_policies) {
@@ -327,6 +331,8 @@ bool ContentSecurityPolicy::allPoliciesWithDispositionAllow(Disposition disposit
 template<typename Predicate, typename... Args>
 bool ContentSecurityPolicy::allPoliciesAllow(ViolatedDirectiveCallback&& callback, Predicate&& predicate, Args&&... args) const
 {
+    if (InspectorInstrumentation::shouldBypassCSP(m_scriptExecutionContext))
+        return true;
     bool isAllowed = true;
     for (auto& policy : m_policies) {
         if (const ContentSecurityPolicyDirective* violatedDirective = (policy.get()->*predicate)(std::forward<Args>(args)...)) {
diff --git a/Source/WebCore/platform/PlatformKeyboardEvent.h b/Source/WebCore/platform/PlatformKeyboardEvent.h
index 16b3719f77d..d96fd15db01 100644
--- a/Source/WebCore/platform/PlatformKeyboardEvent.h
+++ b/Source/WebCore/platform/PlatformKeyboardEvent.h
@@ -132,6 +132,7 @@ namespace WebCore {
         static String keyCodeForHardwareKeyCode(unsigned);
         static String keyIdentifierForGdkKeyCode(unsigned);
         static int windowsKeyCodeForGdkKeyCode(unsigned);
+        static unsigned gdkKeyCodeForWindowsKeyCode(int);
         static String singleCharacterString(unsigned);
         static bool modifiersContainCapsLock(unsigned);
 #endif
@@ -141,6 +142,7 @@ namespace WebCore {
         static String keyCodeForHardwareKeyCode(unsigned);
         static String keyIdentifierForWPEKeyCode(unsigned);
         static int windowsKeyCodeForWPEKeyCode(unsigned);
+        static unsigned WPEKeyCodeForWindowsKeyCode(int);
         static String singleCharacterString(unsigned);
 #endif
 
diff --git a/Source/WebCore/platform/gtk/PlatformKeyboardEventGtk.cpp b/Source/WebCore/platform/gtk/PlatformKeyboardEventGtk.cpp
index 356b09f2fba..8f0c19b6031 100644
--- a/Source/WebCore/platform/gtk/PlatformKeyboardEventGtk.cpp
+++ b/Source/WebCore/platform/gtk/PlatformKeyboardEventGtk.cpp
@@ -36,8 +36,10 @@
 #include "WindowsKeyboardCodes.h"
 #include <gdk/gdk.h>
 #include <gdk/gdkkeysyms.h>
+#include <wtf/HashMap.h>
 #include <wtf/HexNumber.h>
 #include <wtf/glib/GUniquePtr.h>
+#include <mutex>
 
 namespace WebCore {
 
@@ -1293,6 +1295,246 @@ int PlatformKeyboardEvent::windowsKeyCodeForGdkKeyCode(unsigned keycode)
 
 }
 
+static const HashMap<int, unsigned>& gdkToWindowsKeyCodeMap()
+{
+    static HashMap<int, unsigned>* result;
+    static std::once_flag once;
+    std::call_once(
+        once,
+        [] {
+            const unsigned gdkKeyCodes[] = {
+                GDK_KEY_Cancel,
+                // FIXME: non-keypad keys should take precedence, so we skip GDK_KEY_KP_*
+                // GDK_KEY_KP_0,
+                // GDK_KEY_KP_1,
+                // GDK_KEY_KP_2,
+                // GDK_KEY_KP_3,
+                // GDK_KEY_KP_4,
+                // GDK_KEY_KP_5,
+                // GDK_KEY_KP_6,
+                // GDK_KEY_KP_7,
+                // GDK_KEY_KP_8,
+                // GDK_KEY_KP_9,
+                // GDK_KEY_KP_Multiply,
+                // GDK_KEY_KP_Add,
+                // GDK_KEY_KP_Subtract,
+                // GDK_KEY_KP_Decimal,
+                // GDK_KEY_KP_Divide,
+                // GDK_KEY_KP_Page_Up,
+                // GDK_KEY_KP_Page_Down,
+                // GDK_KEY_KP_End,
+                // GDK_KEY_KP_Home,
+                // GDK_KEY_KP_Left,
+                // GDK_KEY_KP_Up,
+                // GDK_KEY_KP_Right,
+                // GDK_KEY_KP_Down,
+                GDK_KEY_BackSpace,
+                // GDK_KEY_ISO_Left_Tab,
+                // GDK_KEY_3270_BackTab,
+                GDK_KEY_Tab,
+                GDK_KEY_Clear,
+                // GDK_KEY_ISO_Enter,
+                // GDK_KEY_KP_Enter,
+                GDK_KEY_Return,
+                GDK_KEY_Menu,
+                GDK_KEY_Pause,
+                GDK_KEY_AudioPause,
+                GDK_KEY_Caps_Lock,
+                GDK_KEY_Kana_Lock,
+                GDK_KEY_Kana_Shift,
+                GDK_KEY_Hangul,
+                GDK_KEY_Hangul_Hanja,
+                GDK_KEY_Kanji,
+                GDK_KEY_Escape,
+                GDK_KEY_space,
+                GDK_KEY_Page_Up,
+                GDK_KEY_Page_Down,
+                GDK_KEY_End,
+                GDK_KEY_Home,
+                GDK_KEY_Left,
+                GDK_KEY_Up,
+                GDK_KEY_Right,
+                GDK_KEY_Down,
+                GDK_KEY_Select,
+                GDK_KEY_Print,
+                GDK_KEY_Execute,
+                GDK_KEY_Insert,
+                GDK_KEY_KP_Insert,
+                GDK_KEY_Delete,
+                GDK_KEY_KP_Delete,
+                GDK_KEY_Help,
+                GDK_KEY_0,
+                GDK_KEY_parenright,
+                GDK_KEY_1,
+                GDK_KEY_exclam,
+                GDK_KEY_2,
+                GDK_KEY_at,
+                GDK_KEY_3,
+                GDK_KEY_numbersign,
+                GDK_KEY_4,
+                GDK_KEY_dollar,
+                GDK_KEY_5,
+                GDK_KEY_percent,
+                GDK_KEY_6,
+                GDK_KEY_asciicircum,
+                GDK_KEY_7,
+                GDK_KEY_ampersand,
+                GDK_KEY_8,
+                GDK_KEY_asterisk,
+                GDK_KEY_9,
+                GDK_KEY_parenleft,
+                GDK_KEY_a,
+                GDK_KEY_A,
+                GDK_KEY_b,
+                GDK_KEY_B,
+                GDK_KEY_c,
+                GDK_KEY_C,
+                GDK_KEY_d,
+                GDK_KEY_D,
+                GDK_KEY_e,
+                GDK_KEY_E,
+                GDK_KEY_f,
+                GDK_KEY_F,
+                GDK_KEY_g,
+                GDK_KEY_G,
+                GDK_KEY_h,
+                GDK_KEY_H,
+                GDK_KEY_i,
+                GDK_KEY_I,
+                GDK_KEY_j,
+                GDK_KEY_J,
+                GDK_KEY_k,
+                GDK_KEY_K,
+                GDK_KEY_l,
+                GDK_KEY_L,
+                GDK_KEY_m,
+                GDK_KEY_M,
+                GDK_KEY_n,
+                GDK_KEY_N,
+                GDK_KEY_o,
+                GDK_KEY_O,
+                GDK_KEY_p,
+                GDK_KEY_P,
+                GDK_KEY_q,
+                GDK_KEY_Q,
+                GDK_KEY_r,
+                GDK_KEY_R,
+                GDK_KEY_s,
+                GDK_KEY_S,
+                GDK_KEY_t,
+                GDK_KEY_T,
+                GDK_KEY_u,
+                GDK_KEY_U,
+                GDK_KEY_v,
+                GDK_KEY_V,
+                GDK_KEY_w,
+                GDK_KEY_W,
+                GDK_KEY_x,
+                GDK_KEY_X,
+                GDK_KEY_y,
+                GDK_KEY_Y,
+                GDK_KEY_z,
+                GDK_KEY_Z,
+                GDK_KEY_Meta_L,
+                GDK_KEY_Meta_R,
+                GDK_KEY_Sleep,
+                GDK_KEY_Num_Lock,
+                GDK_KEY_Scroll_Lock,
+                GDK_KEY_Shift_L,
+                GDK_KEY_Shift_R,
+                GDK_KEY_Control_L,
+                GDK_KEY_Control_R,
+                GDK_KEY_Alt_L,
+                GDK_KEY_Alt_R,
+                GDK_KEY_Back,
+                GDK_KEY_Forward,
+                GDK_KEY_Refresh,
+                GDK_KEY_Stop,
+                GDK_KEY_Search,
+                GDK_KEY_Favorites,
+                GDK_KEY_HomePage,
+                GDK_KEY_AudioMute,
+                GDK_KEY_AudioLowerVolume,
+                GDK_KEY_AudioRaiseVolume,
+                GDK_KEY_AudioNext,
+                GDK_KEY_AudioPrev,
+                GDK_KEY_AudioStop,
+                GDK_KEY_AudioMedia,
+                GDK_KEY_semicolon,
+                GDK_KEY_colon,
+                GDK_KEY_plus,
+                GDK_KEY_equal,
+                GDK_KEY_comma,
+                GDK_KEY_less,
+                GDK_KEY_minus,
+                GDK_KEY_underscore,
+                GDK_KEY_period,
+                GDK_KEY_greater,
+                GDK_KEY_slash,
+                GDK_KEY_question,
+                GDK_KEY_asciitilde,
+                GDK_KEY_quoteleft,
+                GDK_KEY_bracketleft,
+                GDK_KEY_braceleft,
+                GDK_KEY_backslash,
+                GDK_KEY_bar,
+                GDK_KEY_bracketright,
+                GDK_KEY_braceright,
+                GDK_KEY_quoteright,
+                GDK_KEY_quotedbl,
+                GDK_KEY_AudioRewind,
+                GDK_KEY_AudioForward,
+                GDK_KEY_AudioPlay,
+                GDK_KEY_F1,
+                GDK_KEY_F2,
+                GDK_KEY_F3,
+                GDK_KEY_F4,
+                GDK_KEY_F5,
+                GDK_KEY_F6,
+                GDK_KEY_F7,
+                GDK_KEY_F8,
+                GDK_KEY_F9,
+                GDK_KEY_F10,
+                GDK_KEY_F11,
+                GDK_KEY_F12,
+                GDK_KEY_F13,
+                GDK_KEY_F14,
+                GDK_KEY_F15,
+                GDK_KEY_F16,
+                GDK_KEY_F17,
+                GDK_KEY_F18,
+                GDK_KEY_F19,
+                GDK_KEY_F20,
+                GDK_KEY_F21,
+                GDK_KEY_F22,
+                GDK_KEY_F23,
+                GDK_KEY_F24,
+                GDK_KEY_VoidSymbol,
+                GDK_KEY_Red,
+                GDK_KEY_Green,
+                GDK_KEY_Yellow,
+                GDK_KEY_Blue,
+                GDK_KEY_PowerOff,
+                GDK_KEY_AudioRecord,
+                GDK_KEY_Display,
+                GDK_KEY_Subtitle,
+                GDK_KEY_Video
+            };
+            result = new HashMap<int, unsigned>();
+            for (unsigned gdkKeyCode : gdkKeyCodes) {
+                int winKeyCode = PlatformKeyboardEvent::windowsKeyCodeForGdkKeyCode(gdkKeyCode);
+                // If several gdk key codes map to the same win key code first one is used.
+                result->add(winKeyCode, gdkKeyCode);
+            }
+        });
+    return *result;
+}
+
+unsigned PlatformKeyboardEvent::gdkKeyCodeForWindowsKeyCode(int keycode)
+{
+    return gdkToWindowsKeyCodeMap().get(keycode);
+}
+
 String PlatformKeyboardEvent::singleCharacterString(unsigned val)
 {
     switch (val) {
diff --git a/Source/WebCore/platform/libwpe/PlatformKeyboardEventLibWPE.cpp b/Source/WebCore/platform/libwpe/PlatformKeyboardEventLibWPE.cpp
index cf46da15083..efbda20f28b 100644
--- a/Source/WebCore/platform/libwpe/PlatformKeyboardEventLibWPE.cpp
+++ b/Source/WebCore/platform/libwpe/PlatformKeyboardEventLibWPE.cpp
@@ -1291,6 +1291,246 @@ int PlatformKeyboardEvent::windowsKeyCodeForWPEKeyCode(unsigned keycode)
     return 0;
 }
 
+static const HashMap<int, unsigned>& WPEToWindowsKeyCodeMap()
+{
+    static HashMap<int, unsigned>* result;
+    static std::once_flag once;
+    std::call_once(
+        once,
+        [] {
+            const unsigned WPEKeyCodes[] = {
+                WPE_KEY_Cancel,
+                // FIXME: non-keypad keys should take precedence, so we skip WPE_KEY_KP_*
+                // WPE_KEY_KP_0,
+                // WPE_KEY_KP_1,
+                // WPE_KEY_KP_2,
+                // WPE_KEY_KP_3,
+                // WPE_KEY_KP_4,
+                // WPE_KEY_KP_5,
+                // WPE_KEY_KP_6,
+                // WPE_KEY_KP_7,
+                // WPE_KEY_KP_8,
+                // WPE_KEY_KP_9,
+                // WPE_KEY_KP_Multiply,
+                // WPE_KEY_KP_Add,
+                // WPE_KEY_KP_Subtract,
+                // WPE_KEY_KP_Decimal,
+                // WPE_KEY_KP_Divide,
+                // WPE_KEY_KP_Page_Up,
+                // WPE_KEY_KP_Page_Down,
+                // WPE_KEY_KP_End,
+                // WPE_KEY_KP_Home,
+                // WPE_KEY_KP_Left,
+                // WPE_KEY_KP_Up,
+                // WPE_KEY_KP_Right,
+                // WPE_KEY_KP_Down,
+                WPE_KEY_BackSpace,
+                // WPE_KEY_ISO_Left_Tab,
+                // WPE_KEY_3270_BackTab,
+                WPE_KEY_Tab,
+                WPE_KEY_Clear,
+                // WPE_KEY_ISO_Enter,
+                // WPE_KEY_KP_Enter,
+                WPE_KEY_Return,
+                WPE_KEY_Menu,
+                WPE_KEY_Pause,
+                WPE_KEY_AudioPause,
+                WPE_KEY_Caps_Lock,
+                WPE_KEY_Kana_Lock,
+                WPE_KEY_Kana_Shift,
+                WPE_KEY_Hangul,
+                WPE_KEY_Hangul_Hanja,
+                WPE_KEY_Kanji,
+                WPE_KEY_Escape,
+                WPE_KEY_space,
+                WPE_KEY_Page_Up,
+                WPE_KEY_Page_Down,
+                WPE_KEY_End,
+                WPE_KEY_Home,
+                WPE_KEY_Left,
+                WPE_KEY_Up,
+                WPE_KEY_Right,
+                WPE_KEY_Down,
+                WPE_KEY_Select,
+                WPE_KEY_Print,
+                WPE_KEY_Execute,
+                WPE_KEY_Insert,
+                WPE_KEY_KP_Insert,
+                WPE_KEY_Delete,
+                WPE_KEY_KP_Delete,
+                WPE_KEY_Help,
+                WPE_KEY_0,
+                WPE_KEY_parenright,
+                WPE_KEY_1,
+                WPE_KEY_exclam,
+                WPE_KEY_2,
+                WPE_KEY_at,
+                WPE_KEY_3,
+                WPE_KEY_numbersign,
+                WPE_KEY_4,
+                WPE_KEY_dollar,
+                WPE_KEY_5,
+                WPE_KEY_percent,
+                WPE_KEY_6,
+                WPE_KEY_asciicircum,
+                WPE_KEY_7,
+                WPE_KEY_ampersand,
+                WPE_KEY_8,
+                WPE_KEY_asterisk,
+                WPE_KEY_9,
+                WPE_KEY_parenleft,
+                WPE_KEY_a,
+                WPE_KEY_A,
+                WPE_KEY_b,
+                WPE_KEY_B,
+                WPE_KEY_c,
+                WPE_KEY_C,
+                WPE_KEY_d,
+                WPE_KEY_D,
+                WPE_KEY_e,
+                WPE_KEY_E,
+                WPE_KEY_f,
+                WPE_KEY_F,
+                WPE_KEY_g,
+                WPE_KEY_G,
+                WPE_KEY_h,
+                WPE_KEY_H,
+                WPE_KEY_i,
+                WPE_KEY_I,
+                WPE_KEY_j,
+                WPE_KEY_J,
+                WPE_KEY_k,
+                WPE_KEY_K,
+                WPE_KEY_l,
+                WPE_KEY_L,
+                WPE_KEY_m,
+                WPE_KEY_M,
+                WPE_KEY_n,
+                WPE_KEY_N,
+                WPE_KEY_o,
+                WPE_KEY_O,
+                WPE_KEY_p,
+                WPE_KEY_P,
+                WPE_KEY_q,
+                WPE_KEY_Q,
+                WPE_KEY_r,
+                WPE_KEY_R,
+                WPE_KEY_s,
+                WPE_KEY_S,
+                WPE_KEY_t,
+                WPE_KEY_T,
+                WPE_KEY_u,
+                WPE_KEY_U,
+                WPE_KEY_v,
+                WPE_KEY_V,
+                WPE_KEY_w,
+                WPE_KEY_W,
+                WPE_KEY_x,
+                WPE_KEY_X,
+                WPE_KEY_y,
+                WPE_KEY_Y,
+                WPE_KEY_z,
+                WPE_KEY_Z,
+                WPE_KEY_Meta_L,
+                WPE_KEY_Meta_R,
+                WPE_KEY_Sleep,
+                WPE_KEY_Num_Lock,
+                WPE_KEY_Scroll_Lock,
+                WPE_KEY_Shift_L,
+                WPE_KEY_Shift_R,
+                WPE_KEY_Control_L,
+                WPE_KEY_Control_R,
+                WPE_KEY_Alt_L,
+                WPE_KEY_Alt_R,
+                WPE_KEY_Back,
+                WPE_KEY_Forward,
+                WPE_KEY_Refresh,
+                WPE_KEY_Stop,
+                WPE_KEY_Search,
+                WPE_KEY_Favorites,
+                WPE_KEY_HomePage,
+                WPE_KEY_AudioMute,
+                WPE_KEY_AudioLowerVolume,
+                WPE_KEY_AudioRaiseVolume,
+                WPE_KEY_AudioNext,
+                WPE_KEY_AudioPrev,
+                WPE_KEY_AudioStop,
+                WPE_KEY_AudioMedia,
+                WPE_KEY_semicolon,
+                WPE_KEY_colon,
+                WPE_KEY_plus,
+                WPE_KEY_equal,
+                WPE_KEY_comma,
+                WPE_KEY_less,
+                WPE_KEY_minus,
+                WPE_KEY_underscore,
+                WPE_KEY_period,
+                WPE_KEY_greater,
+                WPE_KEY_slash,
+                WPE_KEY_question,
+                WPE_KEY_asciitilde,
+                WPE_KEY_quoteleft,
+                WPE_KEY_bracketleft,
+                WPE_KEY_braceleft,
+                WPE_KEY_backslash,
+                WPE_KEY_bar,
+                WPE_KEY_bracketright,
+                WPE_KEY_braceright,
+                WPE_KEY_quoteright,
+                WPE_KEY_quotedbl,
+                WPE_KEY_AudioRewind,
+                WPE_KEY_AudioForward,
+                WPE_KEY_AudioPlay,
+                WPE_KEY_F1,
+                WPE_KEY_F2,
+                WPE_KEY_F3,
+                WPE_KEY_F4,
+                WPE_KEY_F5,
+                WPE_KEY_F6,
+                WPE_KEY_F7,
+                WPE_KEY_F8,
+                WPE_KEY_F9,
+                WPE_KEY_F10,
+                WPE_KEY_F11,
+                WPE_KEY_F12,
+                WPE_KEY_F13,
+                WPE_KEY_F14,
+                WPE_KEY_F15,
+                WPE_KEY_F16,
+                WPE_KEY_F17,
+                WPE_KEY_F18,
+                WPE_KEY_F19,
+                WPE_KEY_F20,
+                WPE_KEY_F21,
+                WPE_KEY_F22,
+                WPE_KEY_F23,
+                WPE_KEY_F24,
+                WPE_KEY_VoidSymbol,
+                WPE_KEY_Red,
+                WPE_KEY_Green,
+                WPE_KEY_Yellow,
+                WPE_KEY_Blue,
+                WPE_KEY_PowerOff,
+                WPE_KEY_AudioRecord,
+                WPE_KEY_Display,
+                WPE_KEY_Subtitle,
+                WPE_KEY_Video
+            };
+            result = new HashMap<int, unsigned>();
+            for (unsigned WPEKeyCode : WPEKeyCodes) {
+                int winKeyCode = PlatformKeyboardEvent::windowsKeyCodeForWPEKeyCode(WPEKeyCode);
+                // If several gdk key codes map to the same win key code first one is used.
+                result->add(winKeyCode, WPEKeyCode);
+            }
+        });
+    return *result;
+}
+
+unsigned PlatformKeyboardEvent::WPEKeyCodeForWindowsKeyCode(int keycode)
+{
+    return WPEToWindowsKeyCodeMap().get(keycode);
+}
+
 String PlatformKeyboardEvent::singleCharacterString(unsigned val)
 {
     switch (val) {
diff --git a/Source/WebCore/platform/network/soup/NetworkStorageSessionSoup.cpp b/Source/WebCore/platform/network/soup/NetworkStorageSessionSoup.cpp
index 3fb8892c79f..974cd5d8cc3 100644
--- a/Source/WebCore/platform/network/soup/NetworkStorageSessionSoup.cpp
+++ b/Source/WebCore/platform/network/soup/NetworkStorageSessionSoup.cpp
@@ -406,8 +406,13 @@ void NetworkStorageSession::getHostnamesWithCookies(HashSet<String>& hostnames)
 
 Vector<Cookie> NetworkStorageSession::getAllCookies()
 {
-    // FIXME: Implement for WK2 to use.
-    return { };
+    Vector<Cookie> cookies;
+    GUniquePtr<GSList> cookiesList(soup_cookie_jar_all_cookies(cookieStorage()));
+    for (GSList* item = cookiesList.get(); item; item = g_slist_next(item)) {
+        GUniquePtr<SoupCookie> soupCookie(static_cast<SoupCookie*>(item->data));
+        cookies.append(WebCore::Cookie(soupCookie.get()));
+    }
+    return cookies;
 }
 
 Vector<Cookie> NetworkStorageSession::getCookies(const URL& url)
diff --git a/Source/WebKit/NetworkProcess/NetworkProcess.cpp b/Source/WebKit/NetworkProcess/NetworkProcess.cpp
index c32141eba80..ccd58d67e21 100644
--- a/Source/WebKit/NetworkProcess/NetworkProcess.cpp
+++ b/Source/WebKit/NetworkProcess/NetworkProcess.cpp
@@ -26,7 +26,6 @@
 
 #include "config.h"
 #include "NetworkProcess.h"
-
 #include "ArgumentCoders.h"
 #include "Attachment.h"
 #include "AuthenticationManager.h"
@@ -563,6 +562,35 @@ void NetworkProcess::destroySession(PAL::SessionID sessionID)
     m_storageManagerSet->remove(sessionID);
 }
 
+void NetworkProcess::getAllCookies(PAL::SessionID sessionID, CompletionHandler<void(Vector<WebCore::Cookie>&&)>&& completionHandler)
+{
+    if (auto* networkStorageSession = storageSession(sessionID)) {
+        completionHandler(networkStorageSession->getAllCookies());
+        return;
+    }
+    completionHandler({ });
+}
+
+void NetworkProcess::setCookies(PAL::SessionID sessionID, Vector<WebCore::Cookie> cookies, CompletionHandler<void(bool)>&& completionHandler) {
+    if (auto* networkStorageSession = storageSession(sessionID)) {
+        for (auto cookie : cookies)
+            networkStorageSession->setCookie(cookie);
+        completionHandler(true);
+        return;
+    }
+    completionHandler(false);
+}
+
+void NetworkProcess::deleteAllCookies(PAL::SessionID sessionID, CompletionHandler<void(bool)>&& completionHandler)
+{
+    if (auto* networkStorageSession = storageSession(sessionID)) {
+        networkStorageSession->deleteAllCookies();
+        completionHandler(true);
+        return;
+    }
+    completionHandler(false);
+}
+
 #if ENABLE(RESOURCE_LOAD_STATISTICS)
 void NetworkProcess::dumpResourceLoadStatistics(PAL::SessionID sessionID, CompletionHandler<void(String)>&& completionHandler)
 {
diff --git a/Source/WebKit/NetworkProcess/NetworkProcess.h b/Source/WebKit/NetworkProcess/NetworkProcess.h
index cf0ec4de567..a9c3a7d2db3 100644
--- a/Source/WebKit/NetworkProcess/NetworkProcess.h
+++ b/Source/WebKit/NetworkProcess/NetworkProcess.h
@@ -74,6 +74,7 @@ class SessionID;
 
 namespace WebCore {
 class CertificateInfo;
+struct Cookie;
 class CurlProxySettings;
 class DownloadID;
 class ProtectionSpace;
@@ -200,6 +201,10 @@ public:
 
     void addWebsiteDataStore(WebsiteDataStoreParameters&&);
 
+    void getAllCookies(PAL::SessionID, CompletionHandler<void(Vector<WebCore::Cookie>&&)>&&);
+    void setCookies(PAL::SessionID, Vector<WebCore::Cookie>, CompletionHandler<void(bool)>&&);
+    void deleteAllCookies(PAL::SessionID, CompletionHandler<void(bool)>&&);
+
 #if ENABLE(RESOURCE_LOAD_STATISTICS)
     void clearPrevalentResource(PAL::SessionID, const RegistrableDomain&, CompletionHandler<void()>&&);
     void clearUserInteraction(PAL::SessionID, const RegistrableDomain&, CompletionHandler<void()>&&);
@@ -311,6 +316,7 @@ public:
 
 #if PLATFORM(COCOA)
     NetworkHTTPSUpgradeChecker& networkHTTPSUpgradeChecker();
+    bool ignoreTLSErrors() const { return m_ignoreTLSErrors; }
 #endif
 
     const String& uiProcessBundleIdentifier() const { return m_uiProcessBundleIdentifier; }
@@ -418,6 +424,9 @@ private:
     void syncAllCookies();
     void didSyncAllCookies();
 
+#if PLATFORM(COCOA)
+    void setIgnoreTLSErrors(bool);
+#endif
 #if USE(SOUP)
     void setIgnoreTLSErrors(bool);
     void userPreferredLanguagesChanged(const Vector<String>&);
@@ -567,6 +576,7 @@ private:
 
 #if PLATFORM(COCOA)
     std::unique_ptr<NetworkHTTPSUpgradeChecker> m_networkHTTPSUpgradeChecker;
+    bool m_ignoreTLSErrors { false };
 #endif
 
 #if ENABLE(RESOURCE_LOAD_STATISTICS)
diff --git a/Source/WebKit/NetworkProcess/NetworkProcess.messages.in b/Source/WebKit/NetworkProcess/NetworkProcess.messages.in
index 2ad9881fcf7..571f21cfab8 100644
--- a/Source/WebKit/NetworkProcess/NetworkProcess.messages.in
+++ b/Source/WebKit/NetworkProcess/NetworkProcess.messages.in
@@ -27,8 +27,10 @@ messages -> NetworkProcess LegacyReceiver {
     # Creates a connection for communication with a WebProcess
     CreateNetworkConnectionToWebProcess(WebCore::ProcessIdentifier processIdentifier, PAL::SessionID sessionID) -> (Optional<IPC::Attachment> connectionIdentifier) Async
 
-#if USE(SOUP)
+#if USE(SOUP) || PLATFORM(COCOA)
     SetIgnoreTLSErrors(bool ignoreTLSErrors)
+#endif
+#if USE(SOUP)
     UserPreferredLanguagesChanged(Vector<String> languages)
     SetNetworkProxySettings(struct WebCore::SoupNetworkProxySettings settings)
     PrefetchDNS(String hostname)
@@ -80,6 +82,10 @@ messages -> NetworkProcess LegacyReceiver {
     PrepareToSuspend(bool isSuspensionImminent) -> () Async
     ProcessDidResume()
 
+    GetAllCookies(PAL::SessionID sessionID) -> (Vector<WebCore::Cookie> cookies) Async
+    SetCookies(PAL::SessionID sessionID, Vector<WebCore::Cookie> cookies) -> (bool success) Async
+    DeleteAllCookies(PAL::SessionID sessionID) -> (bool success) Async
+
 #if ENABLE(RESOURCE_LOAD_STATISTICS)
     ClearPrevalentResource(PAL::SessionID sessionID, WebCore::RegistrableDomain resourceDomain) -> () Async
     ClearUserInteraction(PAL::SessionID sessionID, WebCore::RegistrableDomain resourceDomain) -> () Async
diff --git a/Source/WebKit/NetworkProcess/NetworkProcessCreationParameters.h b/Source/WebKit/NetworkProcess/NetworkProcessCreationParameters.h
index 715ae67fad6..907d85b5bb6 100644
--- a/Source/WebKit/NetworkProcess/NetworkProcessCreationParameters.h
+++ b/Source/WebKit/NetworkProcess/NetworkProcessCreationParameters.h
@@ -78,9 +78,9 @@ struct NetworkProcessCreationParameters {
 
     WebsiteDataStoreParameters defaultDataStoreParameters;
     
+    bool ignoreTLSErrors { false };
 #if USE(SOUP)
     HTTPCookieAcceptPolicy cookieAcceptPolicy { HTTPCookieAcceptPolicy::AlwaysAccept };
-    bool ignoreTLSErrors { false };
     Vector<String> languages;
     WebCore::SoupNetworkProxySettings proxySettings;
 #endif
diff --git a/Source/WebKit/NetworkProcess/cocoa/NetworkProcessCocoa.mm b/Source/WebKit/NetworkProcess/cocoa/NetworkProcessCocoa.mm
index 4af374b7b41..c4309c782cd 100644
--- a/Source/WebKit/NetworkProcess/cocoa/NetworkProcessCocoa.mm
+++ b/Source/WebKit/NetworkProcess/cocoa/NetworkProcessCocoa.mm
@@ -91,6 +91,8 @@ void NetworkProcess::platformInitializeNetworkProcessCocoa(const NetworkProcessC
 #endif
 #endif
 
+    setIgnoreTLSErrors(parameters.ignoreTLSErrors);
+
     _CFNetworkSetATSContext(parameters.networkATSContext.get());
 
     m_uiProcessBundleIdentifier = parameters.uiProcessBundleIdentifier;
@@ -216,6 +218,7 @@ void NetworkProcess::syncAllCookies()
     });
 }
 
+
 #if HAVE(FOUNDATION_WITH_SAVE_COOKIES_WITH_COMPLETION_HANDLER)
 static void saveCookies(NSHTTPCookieStorage *cookieStorage, CompletionHandler<void()>&& completionHandler)
 {
@@ -246,6 +249,11 @@ void NetworkProcess::platformSyncAllCookies(CompletionHandler<void()>&& completi
     ALLOW_DEPRECATED_DECLARATIONS_END
 }
 
+void NetworkProcess::setIgnoreTLSErrors(bool ignoreTLSErrors)
+{
+    m_ignoreTLSErrors = ignoreTLSErrors;
+}
+
 void NetworkProcess::platformPrepareToSuspend(CompletionHandler<void()>&& completionHandler)
 {
     completionHandler();
diff --git a/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.h b/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.h
index a801b3f4091..76a639b46bc 100644
--- a/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.h
+++ b/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.h
@@ -77,7 +77,7 @@ public:
     const String& dataConnectionServiceType() const;
 #endif
 
-    static bool allowsSpecificHTTPSCertificateForHost(const WebCore::AuthenticationChallenge&);
+    bool allowsSpecificHTTPSCertificateForHost(const WebCore::AuthenticationChallenge&);
 
     void continueDidReceiveChallenge(SessionWrapper&, const WebCore::AuthenticationChallenge&, NetworkDataTaskCocoa::TaskIdentifier, NetworkDataTaskCocoa*, CompletionHandler<void(WebKit::AuthenticationChallengeDisposition, const WebCore::Credential&)>&&);
 
diff --git a/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.mm b/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.mm
index 3a5bd203935..b5048ad1e8f 100644
--- a/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.mm
+++ b/Source/WebKit/NetworkProcess/cocoa/NetworkSessionCocoa.mm
@@ -638,7 +638,7 @@ static inline void processServerTrustEvaluation(NetworkSessionCocoa *session, Se
     }
 
     if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
-        if (NetworkSessionCocoa::allowsSpecificHTTPSCertificateForHost(challenge))
+        if (sessionCocoa->allowsSpecificHTTPSCertificateForHost(challenge))
             return completionHandler(NSURLSessionAuthChallengeUseCredential, [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust]);
 
         // Handle server trust evaluation at platform-level if requested, for performance reasons and to use ATS defaults.
@@ -1302,6 +1302,9 @@ static bool certificatesMatch(SecTrustRef trust1, SecTrustRef trust2)
 
 bool NetworkSessionCocoa::allowsSpecificHTTPSCertificateForHost(const WebCore::AuthenticationChallenge& challenge)
 {
+    if (networkProcess().ignoreTLSErrors())
+        return true;
+
     const String& host = challenge.protectionSpace().host();
     NSArray *certificates = [NSURLRequest allowsSpecificHTTPSCertificateForHost:host];
     if (!certificates)
diff --git a/Source/WebKit/Shared/API/c/wpe/WebKit.h b/Source/WebKit/Shared/API/c/wpe/WebKit.h
index 898e30b370d..74945e06fac 100644
--- a/Source/WebKit/Shared/API/c/wpe/WebKit.h
+++ b/Source/WebKit/Shared/API/c/wpe/WebKit.h
@@ -78,6 +78,7 @@
 // From Source/WebKit/UIProcess/API/C
 #include <WebKit/WKBackForwardListItemRef.h>
 #include <WebKit/WKBackForwardListRef.h>
+#include <WebKit/WKBrowserInspector.h>
 #include <WebKit/WKContext.h>
 #include <WebKit/WKContextConfigurationRef.h>
 #include <WebKit/WKCredential.h>
diff --git a/Source/WebKit/Shared/NativeWebKeyboardEvent.h b/Source/WebKit/Shared/NativeWebKeyboardEvent.h
index 05938ef3564..667882c97db 100644
--- a/Source/WebKit/Shared/NativeWebKeyboardEvent.h
+++ b/Source/WebKit/Shared/NativeWebKeyboardEvent.h
@@ -34,6 +34,7 @@
 #if USE(APPKIT)
 #include <wtf/RetainPtr.h>
 OBJC_CLASS NSView;
+OBJC_CLASS NSEvent;
 
 namespace WebCore {
 struct KeypressCommand;
@@ -65,11 +66,19 @@ public:
 #if USE(APPKIT)
     // FIXME: Share iOS's HandledByInputMethod enum here instead of passing a boolean.
     NativeWebKeyboardEvent(NSEvent *, bool handledByInputMethod, bool replacesSoftSpace, const Vector<WebCore::KeypressCommand>&);
+    NativeWebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp, Vector<WebCore::KeypressCommand>&& commands)
+        : WebKeyboardEvent(type, text, unmodifiedText, key, code, keyIdentifier, windowsVirtualKeyCode, nativeVirtualKeyCode, isAutoRepeat, isKeypad, isSystemKey, modifiers, timestamp, WTFMove(commands))
+    {
+    }
 #elif PLATFORM(GTK)
     NativeWebKeyboardEvent(const NativeWebKeyboardEvent&);
     enum class HandledByInputMethod : bool { No, Yes };
     enum class FakedForComposition : bool { No, Yes };
     NativeWebKeyboardEvent(GdkEvent*, const String&, HandledByInputMethod, FakedForComposition, Vector<String>&& commands);
+    NativeWebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp, Vector<String>&& commands)
+        : WebKeyboardEvent(type, text, unmodifiedText, key, code, keyIdentifier, windowsVirtualKeyCode, nativeVirtualKeyCode, isAutoRepeat, isKeypad, isSystemKey, modifiers, timestamp, WTFMove(commands))
+    {
+    }
 #elif PLATFORM(IOS_FAMILY)
     enum class HandledByInputMethod : bool { No, Yes };
     NativeWebKeyboardEvent(::WebEvent *, HandledByInputMethod);
diff --git a/Source/WebKit/Shared/NativeWebMouseEvent.h b/Source/WebKit/Shared/NativeWebMouseEvent.h
index 0fa557e9faa..60ebade975b 100644
--- a/Source/WebKit/Shared/NativeWebMouseEvent.h
+++ b/Source/WebKit/Shared/NativeWebMouseEvent.h
@@ -61,6 +61,8 @@ public:
 #elif PLATFORM(GTK)
     NativeWebMouseEvent(const NativeWebMouseEvent&);
     NativeWebMouseEvent(GdkEvent*, int, Optional<WebCore::IntPoint>);
+    NativeWebMouseEvent(Type type, Button button, unsigned short buttons, const WebCore::IntPoint& position, const WebCore::IntPoint& globalPosition, float deltaX, float deltaY, float deltaZ, int clickCount, OptionSet<Modifier> modifiers, WallTime timestamp)
+       : WebMouseEvent(type, button, buttons, position, globalPosition, deltaX, deltaY, deltaZ, clickCount, modifiers, timestamp) { }
 #elif PLATFORM(IOS_FAMILY)
     NativeWebMouseEvent(::WebEvent *);
     NativeWebMouseEvent(Type, Button, unsigned short buttons, const WebCore::IntPoint& position, const WebCore::IntPoint& globalPosition, float deltaX, float deltaY, float deltaZ, int clickCount, OptionSet<Modifier>, WallTime timestamp, double force);
diff --git a/Source/WebKit/Shared/WebEvent.h b/Source/WebKit/Shared/WebEvent.h
index f77a16bef13..17a1a8125a9 100644
--- a/Source/WebKit/Shared/WebEvent.h
+++ b/Source/WebKit/Shared/WebEvent.h
@@ -35,6 +35,7 @@
 #include <WebCore/IntSize.h>
 #include <WebCore/KeypressCommand.h>
 #include <wtf/OptionSet.h>
+#include <wtf/RefCounted.h>
 #include <wtf/WallTime.h>
 #include <wtf/text/WTFString.h>
 
@@ -138,7 +139,7 @@ public:
     WebMouseEvent();
 
 #if PLATFORM(MAC)
-    WebMouseEvent(Type, Button, unsigned short buttons, const WebCore::IntPoint& position, const WebCore::IntPoint& globalPosition, float deltaX, float deltaY, float deltaZ, int clickCount, OptionSet<Modifier>, WallTime timestamp, double force, SyntheticClickType = NoTap, int eventNumber = -1, int menuType = 0);
+    WebMouseEvent(Type, Button, unsigned short buttons, const WebCore::IntPoint& position, const WebCore::IntPoint& globalPosition, float deltaX, float deltaY, float deltaZ, int clickCount, OptionSet<Modifier>, WallTime timestamp, double force = 0, SyntheticClickType = NoTap, int eventNumber = -1, int menuType = 0);
 #else
     WebMouseEvent(Type, Button, unsigned short buttons, const WebCore::IntPoint& position, const WebCore::IntPoint& globalPosition, float deltaX, float deltaY, float deltaZ, int clickCount, OptionSet<Modifier>, WallTime timestamp, double force = 0, SyntheticClickType = NoTap);
 #endif
@@ -256,8 +257,10 @@ public:
 
 #if USE(APPKIT)
     WebKeyboardEvent(Type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, int macCharCode, bool handledByInputMethod, const Vector<WebCore::KeypressCommand>&, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier>, WallTime timestamp);
+    WebKeyboardEvent(Type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier>, WallTime timestamp, Vector<WebCore::KeypressCommand>&& commands);
 #elif PLATFORM(GTK)
     WebKeyboardEvent(Type, const String& text, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool handledByInputMethod, Vector<String>&& commands, bool isKeypad, OptionSet<Modifier>, WallTime timestamp);
+    WebKeyboardEvent(Type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier>, WallTime timestamp, Vector<String>&& commands);
 #elif PLATFORM(IOS_FAMILY)
     WebKeyboardEvent(Type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, int macCharCode, bool handledByInputMethod, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier>, WallTime timestamp);
 #elif USE(LIBWPE)
@@ -301,7 +304,7 @@ private:
     int32_t m_nativeVirtualKeyCode;
     int32_t m_macCharCode;
 #if USE(APPKIT) || USE(UIKIT_KEYBOARD_ADDITIONS) || PLATFORM(GTK)
-    bool m_handledByInputMethod;
+    bool m_handledByInputMethod = false;
 #endif
 #if USE(APPKIT)
     Vector<WebCore::KeypressCommand> m_commands;
diff --git a/Source/WebKit/Shared/WebKeyboardEvent.cpp b/Source/WebKit/Shared/WebKeyboardEvent.cpp
index b5955a8b797..9470e947d60 100644
--- a/Source/WebKit/Shared/WebKeyboardEvent.cpp
+++ b/Source/WebKit/Shared/WebKeyboardEvent.cpp
@@ -35,6 +35,7 @@ WebKeyboardEvent::WebKeyboardEvent()
 {
 }
 
+
 #if USE(APPKIT)
 
 WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, int macCharCode, bool handledByInputMethod, const Vector<WebCore::KeypressCommand>& commands, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp)
@@ -56,6 +57,24 @@ WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String&
     ASSERT(isKeyboardEventType(type));
 }
 
+WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp, Vector<WebCore::KeypressCommand>&& commands)
+    : WebEvent(type, modifiers, timestamp)
+    , m_text(text)
+    , m_unmodifiedText(text)
+    , m_key(key)
+    , m_code(code)
+    , m_keyIdentifier(keyIdentifier)
+    , m_windowsVirtualKeyCode(windowsVirtualKeyCode)
+    , m_nativeVirtualKeyCode(nativeVirtualKeyCode)
+    , m_macCharCode(0)
+    , m_commands(WTFMove(commands))
+    , m_isAutoRepeat(isAutoRepeat)
+    , m_isKeypad(isKeypad)
+    , m_isSystemKey(isSystemKey)
+{
+    ASSERT(isKeyboardEventType(type));
+}
+
 #elif PLATFORM(GTK)
 
 WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool handledByInputMethod, Vector<String>&& commands, bool isKeypad, OptionSet<Modifier> modifiers, WallTime timestamp)
@@ -77,6 +96,24 @@ WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String&
     ASSERT(isKeyboardEventType(type));
 }
 
+WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp, Vector<String>&& commands)
+    : WebEvent(type, modifiers, timestamp)
+    , m_text(text)
+    , m_unmodifiedText(text)
+    , m_key(key)
+    , m_code(code)
+    , m_keyIdentifier(keyIdentifier)
+    , m_windowsVirtualKeyCode(windowsVirtualKeyCode)
+    , m_nativeVirtualKeyCode(nativeVirtualKeyCode)
+    , m_macCharCode(0)
+    , m_commands(WTFMove(commands))
+    , m_isAutoRepeat(isAutoRepeat)
+    , m_isKeypad(isKeypad)
+    , m_isSystemKey(isSystemKey)
+{
+    ASSERT(isKeyboardEventType(type));
+}
+
 #elif PLATFORM(IOS_FAMILY)
 
 WebKeyboardEvent::WebKeyboardEvent(Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, const String& keyIdentifier, int windowsVirtualKeyCode, int nativeVirtualKeyCode, int macCharCode, bool handledByInputMethod, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<Modifier> modifiers, WallTime timestamp)
diff --git a/Source/WebKit/Shared/gtk/NativeWebKeyboardEventGtk.cpp b/Source/WebKit/Shared/gtk/NativeWebKeyboardEventGtk.cpp
index 45aa449644b..3a6b4169194 100644
--- a/Source/WebKit/Shared/gtk/NativeWebKeyboardEventGtk.cpp
+++ b/Source/WebKit/Shared/gtk/NativeWebKeyboardEventGtk.cpp
@@ -43,7 +43,7 @@ NativeWebKeyboardEvent::NativeWebKeyboardEvent(GdkEvent* event, const String& te
 }
 
 NativeWebKeyboardEvent::NativeWebKeyboardEvent(const NativeWebKeyboardEvent& event)
-    : WebKeyboardEvent(WebEventFactory::createWebKeyboardEvent(event.nativeEvent(), event.text(), event.handledByInputMethod(), Vector<String>(event.commands())))
+    : WebKeyboardEvent(event)
     , m_nativeEvent(gdk_event_copy(event.nativeEvent()))
     , m_text(event.text())
     , m_handledByInputMethod(event.handledByInputMethod() ? HandledByInputMethod::Yes : HandledByInputMethod::No)
diff --git a/Source/WebKit/Shared/gtk/NativeWebMouseEventGtk.cpp b/Source/WebKit/Shared/gtk/NativeWebMouseEventGtk.cpp
index 58e37fe3827..429d245ea99 100644
--- a/Source/WebKit/Shared/gtk/NativeWebMouseEventGtk.cpp
+++ b/Source/WebKit/Shared/gtk/NativeWebMouseEventGtk.cpp
@@ -38,8 +38,8 @@ NativeWebMouseEvent::NativeWebMouseEvent(GdkEvent* event, int eventClickCount, O
 }
 
 NativeWebMouseEvent::NativeWebMouseEvent(const NativeWebMouseEvent& event)
-    : WebMouseEvent(WebEventFactory::createWebMouseEvent(event.nativeEvent(), event.clickCount(), WebCore::IntPoint(event.deltaX(), event.deltaY())))
-    , m_nativeEvent(gdk_event_copy(event.nativeEvent()))
+    : WebMouseEvent(event)
+    , m_nativeEvent(event.nativeEvent() ? gdk_event_copy(event.nativeEvent()) : nullptr)
 {
 }
 
diff --git a/Source/WebKit/Sources.txt b/Source/WebKit/Sources.txt
index 5424e5dfbb1..5c335d03f41 100644
--- a/Source/WebKit/Sources.txt
+++ b/Source/WebKit/Sources.txt
@@ -247,17 +247,23 @@ Shared/WebsiteData/WebsiteData.cpp
 
 UIProcess/AuxiliaryProcessProxy.cpp
 UIProcess/BackgroundProcessResponsivenessTimer.cpp
+UIProcess/BrowserInspectorController.cpp
+UIProcess/BrowserInspectorPipe.cpp
+UIProcess/BrowserInspectorTargetAgent.cpp
 UIProcess/DeviceIdHashSaltStorage.cpp
 UIProcess/DrawingAreaProxy.cpp
 UIProcess/FrameLoadState.cpp
 UIProcess/GeolocationPermissionRequestManagerProxy.cpp
 UIProcess/GeolocationPermissionRequestProxy.cpp
+UIProcess/InspectorBrowserAgent.cpp
+UIProcess/InspectorDialogAgent.cpp
 UIProcess/InspectorTargetProxy.cpp
 UIProcess/LegacyGlobalSettings.cpp
 UIProcess/PageLoadState.cpp
 UIProcess/ProcessAssertion.cpp
 UIProcess/ProcessThrottler.cpp
 UIProcess/ProvisionalPageProxy.cpp
+UIProcess/RemoteInspectorPipe.cpp
 UIProcess/RemoteWebInspectorProxy.cpp
 UIProcess/ResponsivenessTimer.cpp
 UIProcess/StatisticsRequest.cpp
@@ -299,6 +305,9 @@ UIProcess/WebPageDiagnosticLoggingClient.cpp
 UIProcess/WebPageGroup.cpp
 UIProcess/WebPageInjectedBundleClient.cpp
 UIProcess/WebPageInspectorController.cpp
+UIProcess/WebPageInspectorEmulationAgent.cpp
+UIProcess/WebPageInspectorInputAgent.cpp
+UIProcess/WebPageInspectorTargetProxy.cpp
 UIProcess/WebPageProxy.cpp
 UIProcess/WebPasteboardProxy.cpp
 UIProcess/WebPreferences.cpp
diff --git a/Source/WebKit/SourcesCocoa.txt b/Source/WebKit/SourcesCocoa.txt
index 36f295d3f30..d63c580c6d8 100644
--- a/Source/WebKit/SourcesCocoa.txt
+++ b/Source/WebKit/SourcesCocoa.txt
@@ -249,6 +249,7 @@ UIProcess/API/Cocoa/_WKApplicationManifest.mm
 UIProcess/API/Cocoa/_WKAttachment.mm
 UIProcess/API/Cocoa/_WKAutomationSession.mm
 UIProcess/API/Cocoa/_WKAutomationSessionConfiguration.mm
+UIProcess/API/Cocoa/_WKBrowserInspector.mm
 UIProcess/API/Cocoa/_WKContentRuleListAction.mm
 UIProcess/API/Cocoa/_WKContextMenuElementInfo.mm
 UIProcess/API/Cocoa/_WKCustomHeaderFields.mm @no-unify
diff --git a/Source/WebKit/SourcesGTK.txt b/Source/WebKit/SourcesGTK.txt
index 1a05e334343..33e6d47f028 100644
--- a/Source/WebKit/SourcesGTK.txt
+++ b/Source/WebKit/SourcesGTK.txt
@@ -128,6 +128,7 @@ UIProcess/API/glib/WebKitAuthenticationRequest.cpp @no-unify
 UIProcess/API/glib/WebKitAutomationSession.cpp @no-unify
 UIProcess/API/glib/WebKitBackForwardList.cpp @no-unify
 UIProcess/API/glib/WebKitBackForwardListItem.cpp @no-unify
+UIProcess/API/glib/WebKitBrowserInspector.cpp @no-unify
 UIProcess/API/glib/WebKitContextMenuClient.cpp @no-unify
 UIProcess/API/glib/WebKitCookieManager.cpp @no-unify
 UIProcess/API/glib/WebKitCredential.cpp @no-unify
@@ -224,6 +225,7 @@ UIProcess/WebsiteData/unix/WebsiteDataStoreUnix.cpp
 
 UIProcess/cairo/BackingStoreCairo.cpp @no-unify
 
+UIProcess/glib/InspectorBrowserAgentClientGLib.cpp
 UIProcess/glib/RemoteInspectorClient.cpp
 UIProcess/glib/WebProcessPoolGLib.cpp
 UIProcess/glib/WebProcessProxyGLib.cpp
@@ -252,6 +254,9 @@ UIProcess/gtk/WebColorPickerGtk.cpp
 UIProcess/gtk/WebContextMenuProxyGtk.cpp
 UIProcess/gtk/WebDataListSuggestionsDropdownGtk.cpp
 UIProcess/gtk/WebInspectorProxyGtk.cpp
+UIProcess/gtk/WebPageInspectorEmulationAgentGtk.cpp
+UIProcess/gtk/WebPageInspectorInputAgentGtk.cpp
+UIProcess/gtk/WebPageInspectorTargetProxyGtk.cpp
 UIProcess/gtk/WebKitInspectorWindow.cpp
 UIProcess/gtk/WebPageProxyGtk.cpp @no-unify
 UIProcess/gtk/WebPasteboardProxyGtk.cpp
diff --git a/Source/WebKit/SourcesWPE.txt b/Source/WebKit/SourcesWPE.txt
index 3d200fa60e9..ced6b04bfd2 100644
--- a/Source/WebKit/SourcesWPE.txt
+++ b/Source/WebKit/SourcesWPE.txt
@@ -116,6 +116,7 @@ UIProcess/API/glib/WebKitAuthenticationRequest.cpp @no-unify
 UIProcess/API/glib/WebKitAutomationSession.cpp @no-unify
 UIProcess/API/glib/WebKitBackForwardList.cpp @no-unify
 UIProcess/API/glib/WebKitBackForwardListItem.cpp @no-unify
+UIProcess/API/glib/WebKitBrowserInspector.cpp @no-unify
 UIProcess/API/glib/WebKitContextMenuClient.cpp @no-unify
 UIProcess/API/glib/WebKitCookieManager.cpp @no-unify
 UIProcess/API/glib/WebKitCredential.cpp @no-unify
@@ -184,7 +185,7 @@ UIProcess/Automation/wpe/WebAutomationSessionWPE.cpp
 UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp
 
 UIProcess/geoclue/GeoclueGeolocationProvider.cpp
-
+UIProcess/glib/InspectorBrowserAgentClientGLib.cpp
 UIProcess/glib/WebProcessPoolGLib.cpp
 UIProcess/glib/WebProcessProxyGLib.cpp
 UIProcess/glib/WebsiteDataStoreGLib.cpp @no-unify
@@ -209,6 +210,9 @@ UIProcess/soup/WebProcessPoolSoup.cpp
 UIProcess/wpe/TextCheckerWPE.cpp
 UIProcess/wpe/WebInspectorProxyWPE.cpp
 UIProcess/wpe/WebPageProxyWPE.cpp
+UIProcess/wpe/WebPageInspectorEmulationAgentWPE.cpp
+UIProcess/wpe/WebPageInspectorInputAgentWPE.cpp
+UIProcess/wpe/WebPageInspectorTargetProxyWPE.cpp
 UIProcess/wpe/WebPasteboardProxyWPE.cpp
 UIProcess/wpe/WebPreferencesWPE.cpp
 
diff --git a/Source/WebKit/UIProcess/API/APIUIClient.h b/Source/WebKit/UIProcess/API/APIUIClient.h
index 54513035b26..2d3200e4f6e 100644
--- a/Source/WebKit/UIProcess/API/APIUIClient.h
+++ b/Source/WebKit/UIProcess/API/APIUIClient.h
@@ -97,6 +97,7 @@ public:
     virtual void runJavaScriptAlert(WebKit::WebPageProxy&, const WTF::String&, WebKit::WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void()>&& completionHandler) { completionHandler(); }
     virtual void runJavaScriptConfirm(WebKit::WebPageProxy&, const WTF::String&, WebKit::WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void(bool)>&& completionHandler) { completionHandler(false); }
     virtual void runJavaScriptPrompt(WebKit::WebPageProxy&, const WTF::String&, const WTF::String&, WebKit::WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void(const WTF::String&)>&& completionHandler) { completionHandler(WTF::String()); }
+    virtual void handleJavaScriptDialog(WebKit::WebPageProxy&, bool, const WTF::String&) { }
 
     virtual void setStatusText(WebKit::WebPageProxy*, const WTF::String&) { }
     virtual void mouseDidMoveOverElement(WebKit::WebPageProxy&, const WebKit::WebHitTestResultData&, OptionSet<WebKit::WebEvent::Modifier>, Object*) { }
diff --git a/Source/WebKit/UIProcess/API/C/WKPage.cpp b/Source/WebKit/UIProcess/API/C/WKPage.cpp
index 70efbfa3e87..0ef2a77bb3e 100644
--- a/Source/WebKit/UIProcess/API/C/WKPage.cpp
+++ b/Source/WebKit/UIProcess/API/C/WKPage.cpp
@@ -1675,6 +1675,8 @@ void WKPageSetPageUIClient(WKPageRef pageRef, const WKPageUIClientBase* wkClient
             completionHandler(String());
         }
 
+        void handleJavaScriptDialog(WebPageProxy&, bool, const String&) final { }
+
         void setStatusText(WebPageProxy* page, const String& text) final
         {
             if (!m_client.setStatusText)
@@ -1735,6 +1737,8 @@ void WKPageSetPageUIClient(WKPageRef pageRef, const WKPageUIClientBase* wkClient
         {
             if (!m_client.didNotHandleKeyEvent)
                 return;
+            if (!event.nativeEvent())
+                return;
             m_client.didNotHandleKeyEvent(toAPI(page), event.nativeEvent(), m_client.base.clientInfo);
         }
 
diff --git a/Source/WebKit/UIProcess/API/Cocoa/WKUIDelegate.h b/Source/WebKit/UIProcess/API/Cocoa/WKUIDelegate.h
index cad87f3ef2a..66145a38463 100644
--- a/Source/WebKit/UIProcess/API/Cocoa/WKUIDelegate.h
+++ b/Source/WebKit/UIProcess/API/Cocoa/WKUIDelegate.h
@@ -123,6 +123,13 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * _Nullable result))completionHandler;
 
+/*! @abstract Handle a JavaScript dialog.
+ @param webView The web view invoking the delegate method.
+ @param accept Whether to accept the dialog.
+ @param value Value to use for prompt dialog.
+ */
+- (void)webView:(WKWebView *)webView handleJavaScriptDialog:(BOOL)accept value:(nullable NSString *)value;
+
 #if TARGET_OS_IPHONE
 
 /*! @abstract Allows your app to determine whether or not the given element should show a preview.
diff --git a/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.h b/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.h
index 726c4972aa0..c67f4087977 100644
--- a/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.h
+++ b/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.h
@@ -24,7 +24,6 @@
  */
 
 #import <WebKit/WKFoundation.h>
-
 #import <WebKit/WKWebsiteDataRecord.h>
 
 NS_ASSUME_NONNULL_BEGIN
@@ -78,6 +77,8 @@ WK_CLASS_AVAILABLE(macos(10.11), ios(9.0))
 /*! @abstract Returns the cookie store representing HTTP cookies in this website data store. */
 @property (nonatomic, readonly) WKHTTPCookieStore *httpCookieStore WK_API_AVAILABLE(macos(10.13), ios(11.0));
 
+- (uint64_t)sessionID;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.mm b/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.mm
index 538373d069c..f85dc4c124f 100644
--- a/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.mm
+++ b/Source/WebKit/UIProcess/API/Cocoa/WKWebsiteDataStore.mm
@@ -44,6 +44,7 @@
 #import "_WKWebsiteDataStoreDelegate.h"
 #import <WebCore/Credential.h>
 #import <WebCore/RegistrationDatabase.h>
+#import <pal/SessionID.h>
 #import <wtf/BlockPtr.h>
 #import <wtf/URL.h>
 #import <wtf/WeakObjCPtr.h>
@@ -184,6 +185,11 @@ static WallTime toSystemClockTime(NSDate *date)
     });
 }
 
+- (uint64_t) sessionID
+{
+    return _websiteDataStore->sessionID().toUInt64();
+}
+
 static Vector<WebKit::WebsiteDataRecord> toWebsiteDataRecords(NSArray *dataRecords)
 {
     Vector<WebKit::WebsiteDataRecord> result;
diff --git a/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.h b/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.h
new file mode 100644
index 00000000000..7ed58e57553
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.h
@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#import <WebKit/WKFoundation.h>
+#import <WebKit/WKProcessPool.h>
+#import <WebKit/WKWebsiteDataStore.h>
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class WKWebView;
+
+WK_CLASS_AVAILABLE(macos(10.14.0))
+@interface _WKBrowserContext : NSObject
+@property (nonatomic, strong) WKWebsiteDataStore *dataStore;
+@property (nonatomic, strong) WKProcessPool *processPool;
+@end
+
+@protocol _WKBrowserInspectorDelegate <NSObject>
+- (WKWebView *)createNewPage:(uint64_t)sessionID;
+- (_WKBrowserContext *)createBrowserContext;
+- (void)deleteBrowserContext:(uint64_t)sessionID;
+- (void)quit;
+@end
+
+WK_CLASS_AVAILABLE(macos(10.14.0))
+@interface _WKBrowserInspector : NSObject
++ (void)initializeRemoteInspectorPipe:(id<_WKBrowserInspectorDelegate>)delegate headless:(BOOL)headless;
+@end
+
+
+NS_ASSUME_NONNULL_END
+
diff --git a/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.mm b/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.mm
new file mode 100644
index 00000000000..b0bdfb97e28
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/Cocoa/_WKBrowserInspector.mm
@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "_WKBrowserInspector.h"
+
+#include "BrowserInspectorPipe.h"
+#include "InspectorBrowserAgentClientMac.h"
+#include "PageClientImplMac.h"
+#include "WebsiteDataStore.h"
+
+#import "WKWebView.h"
+
+using namespace WebKit;
+
+@implementation _WKBrowserInspector
+
++ (void)initializeRemoteInspectorPipe:(id<_WKBrowserInspectorDelegate>)delegate headless:(BOOL)headless
+{
+#if ENABLE(REMOTE_INSPECTOR)
+  WebsiteDataStore::defaultDataStore();
+  PageClientImpl::setHeadless(headless);
+  initializeBrowserInspectorPipe(makeUnique<InspectorBrowserAgentClientMac>(delegate));
+#endif
+}
+
+@end
+
+@implementation _WKBrowserContext
+@end
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspector.cpp b/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspector.cpp
new file mode 100644
index 00000000000..c21192686c9
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspector.cpp
@@ -0,0 +1,114 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebKitBrowserInspector.h"
+
+#include "BrowserInspectorPipe.h"
+#include "InspectorBrowserAgentClientGLib.h"
+#include "WebKitBrowserInspectorPrivate.h"
+#include "WebKitWebViewPrivate.h"
+#include <wtf/glib/GRefPtr.h>
+#include <wtf/glib/WTFGType.h>
+
+/**
+ * SECTION: WebKitBrowserInspector
+ * @Short_description: Access to the WebKit browser inspector
+ * @Title: WebKitBrowserInspector
+ *
+ * The WebKit Browser Inspector is an experimental API that provides
+ * access to the inspector via the remote debugging protocol. The protocol
+ * allows to create ephemeral contexts and create pages in them and then
+ * manipulate them using the inspector commands. This may be useful for
+ * the browser automation or remote debugging.
+ *
+ * Currently the protocol can be exposed to the parent process via a unix
+ * pipe.
+ */
+
+enum {
+    CREATE_NEW_PAGE,
+
+    LAST_SIGNAL
+};
+
+struct _WebKitBrowserInspectorPrivate {
+    int unused { 0 };
+};
+
+WEBKIT_DEFINE_TYPE(WebKitBrowserInspector, webkit_browser_inspector, G_TYPE_OBJECT)
+
+static guint signals[LAST_SIGNAL] = { 0, };
+
+static void webkit_browser_inspector_class_init(WebKitBrowserInspectorClass* findClass)
+{
+    GObjectClass* gObjectClass = G_OBJECT_CLASS(findClass);
+
+    /**
+     * WebKitBrowserInspector::create-new-page:
+     * @inspector: the #WebKitBrowserInspector on which the signal is emitted
+     *
+     * Emitted when the inspector is requested to create a new page in the provided
+     * #WebKitWebContext.
+     *
+     * This signal is emitted when inspector receives 'Browser.createPage' command
+     * from its remote client. If the signla is not handled the command will fail.
+     *
+     * Returns: %WebKitWebView that contains created page.
+     */
+    signals[CREATE_NEW_PAGE] = g_signal_new(
+        "create-new-page",
+        G_TYPE_FROM_CLASS(gObjectClass),
+        G_SIGNAL_RUN_LAST,
+        G_STRUCT_OFFSET(WebKitBrowserInspectorClass, create_new_page),
+        nullptr, nullptr,
+        g_cclosure_marshal_generic,
+#if PLATFORM(GTK)
+        GTK_TYPE_WIDGET,
+#else
+        WEBKIT_TYPE_WEB_VIEW,
+#endif
+        1,
+        WEBKIT_TYPE_WEB_CONTEXT);
+}
+
+WebKit::WebPageProxy* webkitBrowserInspectorCreateNewPageInContext(WebKitWebContext* context)
+{
+    WebKitWebView* newWebView;
+    g_signal_emit(webkit_browser_inspector_get_default(), signals[CREATE_NEW_PAGE], 0, context, &newWebView);
+    if (!newWebView)
+        return nullptr;
+    return  &webkitWebViewGetPage(newWebView);
+}
+
+static gpointer createWebKitBrowserInspector(gpointer)
+{
+    static GRefPtr<WebKitBrowserInspector> browserInspector = adoptGRef(WEBKIT_BROWSER_INSPECTOR(g_object_new(WEBKIT_TYPE_BROWSER_INSPECTOR, nullptr)));
+    return browserInspector.get();
+}
+
+/**
+ * webkit_browser_inspector_get_default:
+ *
+ * Gets the default instance of the browser inspector.
+ *
+ * Returns: (transfer none): a #WebKitBrowserInspector
+ */
+WebKitBrowserInspector* webkit_browser_inspector_get_default(void)
+{
+    static GOnce onceInit = G_ONCE_INIT;
+    return WEBKIT_BROWSER_INSPECTOR(g_once(&onceInit, createWebKitBrowserInspector, 0));
+}
+
+/**
+ * webkit_browser_inspector_initialize_pipe:
+ *
+ * Creates browser inspector and configures pipe handler to communicate with
+ * the parent process.
+ */
+void webkit_browser_inspector_initialize_pipe(void)
+{
+#if ENABLE(REMOTE_INSPECTOR)
+    WebKit::initializeBrowserInspectorPipe(makeUnique<WebKit::InspectorBrowserAgentClientGlib>());
+#endif
+}
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspectorPrivate.h b/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspectorPrivate.h
new file mode 100644
index 00000000000..ab6b7621d10
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/glib/WebKitBrowserInspectorPrivate.h
@@ -0,0 +1,9 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "WebKitBrowserInspector.h"
+#include "WebPageProxy.h"
+
+WebKit::WebPageProxy* webkitBrowserInspectorCreateNewPageInContext(WebKitWebContext*);
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitUIClient.cpp b/Source/WebKit/UIProcess/API/glib/WebKitUIClient.cpp
index f769407fdc6..ba010ed593b 100644
--- a/Source/WebKit/UIProcess/API/glib/WebKitUIClient.cpp
+++ b/Source/WebKit/UIProcess/API/glib/WebKitUIClient.cpp
@@ -91,6 +91,10 @@ private:
     {
         webkitWebViewRunJavaScriptPrompt(m_webView, message.utf8(), defaultValue.utf8(), WTFMove(completionHandler));
     }
+    void handleJavaScriptDialog(WebPageProxy&, bool accept, const String& value) final
+    {
+        webkitWebViewHandleJavaScriptDialog(m_webView, accept, value);
+    }
 
     bool canRunBeforeUnloadConfirmPanel() const final { return true; }
 
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp b/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
index 33a9b7d5ad0..406c6431bd8 100644
--- a/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
+++ b/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
@@ -385,6 +385,11 @@ static void webkitWebContextConstructed(GObject* object)
     if (!webkit_website_data_manager_is_ephemeral(priv->websiteDataManager.get()))
         WebKit::LegacyGlobalSettings::singleton().setHSTSStorageDirectory(FileSystem::stringFromFileSystemRepresentation(webkit_website_data_manager_get_hsts_cache_directory(priv->websiteDataManager.get())));
 
+    const gchar *singleprocess = g_getenv("MINIBROWSER_SINGLEPROCESS");
+    if (singleprocess && *singleprocess) {
+        // processModel is not set at this point, force single process.
+        configuration.setUsesSingleWebProcess(true);
+    }
     priv->processPool = WebProcessPool::create(configuration);
     priv->processPool->setPrimaryDataStore(webkitWebsiteDataManagerGetDataStore(priv->websiteDataManager.get()));
     priv->processPool->setUserMessageHandler([webContext](UserMessage&& message, CompletionHandler<void(UserMessage&&)>&& completionHandler) {
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitWebView.cpp b/Source/WebKit/UIProcess/API/glib/WebKitWebView.cpp
index d21c782eded..c42842b14a7 100644
--- a/Source/WebKit/UIProcess/API/glib/WebKitWebView.cpp
+++ b/Source/WebKit/UIProcess/API/glib/WebKitWebView.cpp
@@ -2379,6 +2379,15 @@ void webkitWebViewRunJavaScriptBeforeUnloadConfirm(WebKitWebView* webView, const
     webkit_script_dialog_unref(webView->priv->currentScriptDialog);
 }
 
+void webkitWebViewHandleJavaScriptDialog(WebKitWebView* webView, bool accept, const String& value) {
+    if (!value.isNull())
+        webkitWebViewSetCurrentScriptDialogUserInput(webView, value);
+    if (accept)
+        webkitWebViewAcceptCurrentScriptDialog(webView);
+    else
+        webkitWebViewDismissCurrentScriptDialog(webView);
+}
+
 bool webkitWebViewIsShowingScriptDialog(WebKitWebView* webView)
 {
     if (!webView->priv->currentScriptDialog)
diff --git a/Source/WebKit/UIProcess/API/glib/WebKitWebViewPrivate.h b/Source/WebKit/UIProcess/API/glib/WebKitWebViewPrivate.h
index a5f99b325dd..9ab1efc678b 100644
--- a/Source/WebKit/UIProcess/API/glib/WebKitWebViewPrivate.h
+++ b/Source/WebKit/UIProcess/API/glib/WebKitWebViewPrivate.h
@@ -58,6 +58,7 @@ void webkitWebViewRunJavaScriptAlert(WebKitWebView*, const CString& message, Fun
 void webkitWebViewRunJavaScriptConfirm(WebKitWebView*, const CString& message, Function<void(bool)>&& completionHandler);
 void webkitWebViewRunJavaScriptPrompt(WebKitWebView*, const CString& message, const CString& defaultText, Function<void(const String&)>&& completionHandler);
 void webkitWebViewRunJavaScriptBeforeUnloadConfirm(WebKitWebView*, const CString& message, Function<void(bool)>&& completionHandler);
+void webkitWebViewHandleJavaScriptDialog(WebKitWebView*, bool accept, const String& value);
 bool webkitWebViewIsShowingScriptDialog(WebKitWebView*);
 bool webkitWebViewIsScriptDialogRunning(WebKitWebView*, WebKitScriptDialog*);
 String webkitWebViewGetCurrentScriptDialogMessage(WebKitWebView*);
diff --git a/Source/WebKit/UIProcess/API/gtk/PageClientImpl.cpp b/Source/WebKit/UIProcess/API/gtk/PageClientImpl.cpp
index 00b7c6bbc46..c3a6cf416e1 100644
--- a/Source/WebKit/UIProcess/API/gtk/PageClientImpl.cpp
+++ b/Source/WebKit/UIProcess/API/gtk/PageClientImpl.cpp
@@ -226,6 +226,8 @@ void PageClientImpl::doneWithKeyEvent(const NativeWebKeyboardEvent& event, bool
         return;
     if (event.fakedForComposition())
         return;
+    if (!event.nativeEvent())
+        return;
 
     WebKitWebViewBase* webkitWebViewBase = WEBKIT_WEB_VIEW_BASE(m_viewWidget);
     webkitWebViewBaseForwardNextKeyEvent(webkitWebViewBase);
diff --git a/Source/WebKit/UIProcess/API/gtk/WebKitBrowserInspector.h b/Source/WebKit/UIProcess/API/gtk/WebKitBrowserInspector.h
new file mode 100644
index 00000000000..9bd1cd6c216
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/gtk/WebKitBrowserInspector.h
@@ -0,0 +1,57 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#if !defined(__WEBKIT2_H_INSIDE__) && !defined(WEBKIT2_COMPILATION)
+#error "Only <webkit2/webkit2.h> can be included directly."
+#endif
+
+#ifndef WebKitBrowserInspector_h
+#define WebKitBrowserInspector_h
+
+#include <glib-object.h>
+#include <webkit2/WebKitDefines.h>
+#include <webkit2/WebKitWebView.h>
+
+G_BEGIN_DECLS
+
+#define WEBKIT_TYPE_BROWSER_INSPECTOR            (webkit_browser_inspector_get_type())
+#define WEBKIT_BROWSER_INSPECTOR(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj), WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspector))
+#define WEBKIT_IS_BROWSER_INSPECTOR(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), WEBKIT_TYPE_BROWSER_INSPECTOR))
+#define WEBKIT_BROWSER_INSPECTOR_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),  WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspectorClass))
+#define WEBKIT_IS_BROWSER_INSPECTOR_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),  WEBKIT_TYPE_BROWSER_INSPECTOR))
+#define WEBKIT_BROWSER_INSPECTOR_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj),  WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspectorClass))
+
+typedef struct _WebKitBrowserInspector        WebKitBrowserInspector;
+typedef struct _WebKitBrowserInspectorClass   WebKitBrowserInspectorClass;
+typedef struct _WebKitBrowserInspectorPrivate WebKitBrowserInspectorPrivate;
+
+struct _WebKitBrowserInspector {
+    GObject parent;
+
+    WebKitBrowserInspectorPrivate *priv;
+};
+
+struct _WebKitBrowserInspectorClass {
+    GObjectClass parent_class;
+
+    WebKitWebView *(* create_new_page)           (WebKitBrowserInspector    *browser_inspector,
+                                                  WebKitWebContext          *context);
+
+    void (*_webkit_reserved0) (void);
+    void (*_webkit_reserved1) (void);
+    void (*_webkit_reserved2) (void);
+    void (*_webkit_reserved3) (void);
+};
+
+WEBKIT_API GType
+webkit_browser_inspector_get_type                     (void);
+
+WEBKIT_API WebKitBrowserInspector *
+webkit_browser_inspector_get_default                  (void);
+
+WEBKIT_API void
+webkit_browser_inspector_initialize_pipe              (void);
+
+G_END_DECLS
+
+#endif
diff --git a/Source/WebKit/UIProcess/API/gtk/webkit2.h b/Source/WebKit/UIProcess/API/gtk/webkit2.h
index 4c196217e6f..a7208990a7e 100644
--- a/Source/WebKit/UIProcess/API/gtk/webkit2.h
+++ b/Source/WebKit/UIProcess/API/gtk/webkit2.h
@@ -32,6 +32,7 @@
 #include <webkit2/WebKitAutomationSession.h>
 #include <webkit2/WebKitBackForwardList.h>
 #include <webkit2/WebKitBackForwardListItem.h>
+#include <webkit2/WebKitBrowserInspector.h>
 #include <webkit2/WebKitContextMenu.h>
 #include <webkit2/WebKitContextMenuActions.h>
 #include <webkit2/WebKitContextMenuItem.h>
diff --git a/Source/WebKit/UIProcess/API/wpe/WebKitBrowserInspector.h b/Source/WebKit/UIProcess/API/wpe/WebKitBrowserInspector.h
new file mode 100644
index 00000000000..11fde7598a3
--- /dev/null
+++ b/Source/WebKit/UIProcess/API/wpe/WebKitBrowserInspector.h
@@ -0,0 +1,54 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#if !defined(__WEBKIT_H_INSIDE__) && !defined(WEBKIT2_COMPILATION)
+#error "Only <wpe/webkit.h> can be included directly."
+#endif
+
+#ifndef WebKitBrowserInspector_h
+#define WebKitBrowserInspector_h
+
+#include <glib-object.h>
+#include <wpe/WebKitDefines.h>
+#include <wpe/WebKitWebView.h>
+
+G_BEGIN_DECLS
+
+#define WEBKIT_TYPE_BROWSER_INSPECTOR            (webkit_browser_inspector_get_type())
+#define WEBKIT_BROWSER_INSPECTOR(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj), WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspector))
+#define WEBKIT_IS_BROWSER_INSPECTOR(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), WEBKIT_TYPE_BROWSER_INSPECTOR))
+#define WEBKIT_BROWSER_INSPECTOR_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass),  WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspectorClass))
+#define WEBKIT_IS_BROWSER_INSPECTOR_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),  WEBKIT_TYPE_BROWSER_INSPECTOR))
+#define WEBKIT_BROWSER_INSPECTOR_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj),  WEBKIT_TYPE_BROWSER_INSPECTOR, WebKitBrowserInspectorClass))
+
+typedef struct _WebKitBrowserInspector        WebKitBrowserInspector;
+typedef struct _WebKitBrowserInspectorClass   WebKitBrowserInspectorClass;
+typedef struct _WebKitBrowserInspectorPrivate WebKitBrowserInspectorPrivate;
+
+struct _WebKitBrowserInspector {
+    GObject parent;
+
+    WebKitBrowserInspectorPrivate *priv;
+};
+
+struct _WebKitBrowserInspectorClass {
+    GObjectClass parent_class;
+
+    WebKitWebView *(* create_new_page)           (WebKitBrowserInspector    *browser_inspector,
+                                                  WebKitWebContext          *context);
+
+    void (*_webkit_reserved0) (void);
+    void (*_webkit_reserved1) (void);
+    void (*_webkit_reserved2) (void);
+    void (*_webkit_reserved3) (void);
+};
+
+WEBKIT_API GType
+webkit_browser_inspector_get_type                     (void);
+
+WEBKIT_API WebKitBrowserInspector *
+webkit_browser_inspector_get_default                  (void);
+
+G_END_DECLS
+
+#endif
diff --git a/Source/WebKit/UIProcess/API/wpe/webkit.h b/Source/WebKit/UIProcess/API/wpe/webkit.h
index 9cc31cb4968..930499e65b6 100644
--- a/Source/WebKit/UIProcess/API/wpe/webkit.h
+++ b/Source/WebKit/UIProcess/API/wpe/webkit.h
@@ -32,6 +32,7 @@
 #include <wpe/WebKitAutomationSession.h>
 #include <wpe/WebKitBackForwardList.h>
 #include <wpe/WebKitBackForwardListItem.h>
+#include <wpe/WebKitBrowserInspector.h>
 #include <wpe/WebKitContextMenu.h>
 #include <wpe/WebKitContextMenuActions.h>
 #include <wpe/WebKitContextMenuItem.h>
diff --git a/Source/WebKit/UIProcess/BrowserInspectorController.cpp b/Source/WebKit/UIProcess/BrowserInspectorController.cpp
new file mode 100644
index 00000000000..260916b29cf
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorController.cpp
@@ -0,0 +1,116 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "BrowserInspectorController.h"
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "BrowserInspectorTargetAgent.h"
+#include "InspectorBrowserAgent.h"
+#include "InspectorBrowserAgentClient.h"
+#include "WebPageInspectorController.h"
+#include "WebPageProxy.h"
+#include "WebProcessPool.h"
+#include "WebProcessProxy.h"
+#include <JavaScriptCore/InspectorBackendDispatcher.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+#include <JavaScriptCore/InspectorFrontendChannel.h>
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+#include <JavaScriptCore/InspectorTarget.h>
+#include <wtf/Ref.h>
+#include <wtf/RefPtr.h>
+
+using namespace Inspector;
+
+namespace WebKit {
+
+static Vector<WebPageProxy*> allPages()
+{
+    ASSERT(isMainThread());
+    Vector<WebPageProxy*> result;
+    for (WebProcessPool* pool : WebProcessPool::allProcessPools()) {
+        for (auto& process : pool->processes()) {
+            result.appendRange(process->pages().begin(), process->pages().end());
+        }
+    }
+    return result;
+}
+
+BrowserInspectorController::BrowserInspectorController(std::unique_ptr<InspectorBrowserAgentClient> client)
+    : m_frontendChannel(nullptr)
+    , m_frontendRouter(FrontendRouter::create())
+    , m_backendDispatcher(BackendDispatcher::create(m_frontendRouter.copyRef()))
+    , m_browserAgentClient(std::move(client))
+{
+    m_agents.append(makeUnique<InspectorBrowserAgent>(m_backendDispatcher, m_browserAgentClient.get()));
+    auto targetAgent = makeUnique<BrowserInspectorTargetAgent>(m_backendDispatcher);
+    m_browserTargetAgent = targetAgent.get();
+    m_agents.append(WTFMove(targetAgent));
+}
+
+BrowserInspectorController::~BrowserInspectorController()
+{
+    if (m_frontendChannel)
+        disconnectFrontend();
+}
+
+void BrowserInspectorController::connectFrontend(FrontendChannel& frontendChannel)
+{
+    ASSERT(!m_frontendChannel);
+    m_frontendChannel = &frontendChannel;
+    WebPageInspectorController::setObserver(this);
+
+    bool connectingFirstFrontend = !m_frontendRouter->hasFrontends();
+    m_frontendRouter->connectFrontend(frontendChannel);
+    if (connectingFirstFrontend)
+        m_agents.didCreateFrontendAndBackend(&m_frontendRouter.get(), &m_backendDispatcher.get());
+
+    connectToAllPages();
+}
+
+void BrowserInspectorController::disconnectFrontend()
+{
+    ASSERT(m_frontendChannel);
+    disconnectFromAllPages();
+
+    m_frontendRouter->disconnectFrontend(*m_frontendChannel);
+    if (!m_frontendRouter->hasFrontends())
+        m_agents.willDestroyFrontendAndBackend(DisconnectReason::InspectorDestroyed);
+
+    WebPageInspectorController::setObserver(nullptr);
+    m_frontendChannel = nullptr;
+}
+
+void BrowserInspectorController::dispatchMessageFromFrontend(const String& message)
+{
+    m_backendDispatcher->dispatch(message);
+}
+
+void BrowserInspectorController::connectToAllPages()
+{
+    for (auto* page : allPages())
+        page->inspectorController().connectFrontend(*m_frontendChannel);
+}
+
+void BrowserInspectorController::disconnectFromAllPages()
+{
+    for (auto* page : allPages())
+        page->inspectorController().disconnectFrontend(*m_frontendChannel);
+}
+
+void BrowserInspectorController::didCreateInspectorController(WebPageInspectorController& inspectorController)
+{
+    ASSERT(m_frontendChannel);
+    // Auto-connect to all new pages.
+    inspectorController.connectFrontend(*m_frontendChannel);
+}
+
+void BrowserInspectorController::didCreateTarget(InspectorTarget& target)
+{
+    m_browserTargetAgent->didCreateTarget(target);
+}
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/BrowserInspectorController.h b/Source/WebKit/UIProcess/BrowserInspectorController.h
new file mode 100644
index 00000000000..c487dd06ce4
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorController.h
@@ -0,0 +1,55 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "WebPageInspectorController.h"
+#include <JavaScriptCore/InspectorAgentRegistry.h>
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class BackendDispatcher;
+class FrontendChannel;
+class FrontendRouter;
+}
+
+namespace WebKit {
+
+class BrowserInspectorTargetAgent;
+class InspectorBrowserAgentClient;
+
+class BrowserInspectorController : private WebPageInspectorControllerObserver {
+    WTF_MAKE_NONCOPYABLE(BrowserInspectorController);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    BrowserInspectorController(std::unique_ptr<InspectorBrowserAgentClient> client);
+    ~BrowserInspectorController();
+
+    void connectFrontend(Inspector::FrontendChannel&);
+    void disconnectFrontend();
+    void dispatchMessageFromFrontend(const String& message);
+
+private:
+    class TargetHandler;
+
+    // WebPageInspectorControllerObserver
+    void didCreateInspectorController(WebPageInspectorController&) override;
+    void didCreateTarget(Inspector::InspectorTarget&) override;
+
+    void connectToAllPages();
+    void disconnectFromAllPages();
+
+    Inspector::FrontendChannel* m_frontendChannel { nullptr };
+    Ref<Inspector::FrontendRouter> m_frontendRouter;
+    Ref<Inspector::BackendDispatcher> m_backendDispatcher;
+    std::unique_ptr<InspectorBrowserAgentClient> m_browserAgentClient;
+    Inspector::AgentRegistry m_agents;
+    BrowserInspectorTargetAgent* m_browserTargetAgent { nullptr };
+};
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/BrowserInspectorPipe.cpp b/Source/WebKit/UIProcess/BrowserInspectorPipe.cpp
new file mode 100644
index 00000000000..46f05a2a45f
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorPipe.cpp
@@ -0,0 +1,35 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "BrowserInspectorPipe.h"
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "BrowserInspectorController.h"
+#include "RemoteInspectorPipe.h"
+#include <wtf/NeverDestroyed.h>
+#include "InspectorBrowserAgentClient.h"
+
+namespace WebKit {
+
+void initializeBrowserInspectorPipe(std::unique_ptr<InspectorBrowserAgentClient> client)
+{
+    class BrowserInspectorPipe {
+    public:
+        BrowserInspectorPipe(std::unique_ptr<InspectorBrowserAgentClient> client)
+            : m_browserInspectorController(std::move(client))
+            , m_remoteInspectorPipe(m_browserInspectorController)
+        {
+        }
+
+        BrowserInspectorController m_browserInspectorController;
+        RemoteInspectorPipe m_remoteInspectorPipe;
+    };
+
+    static NeverDestroyed<BrowserInspectorPipe> pipe(std::move(client));
+}
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/BrowserInspectorPipe.h b/Source/WebKit/UIProcess/BrowserInspectorPipe.h
new file mode 100644
index 00000000000..ac0caaabaed
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorPipe.h
@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+namespace WebKit {
+
+class InspectorBrowserAgentClient;
+
+void initializeBrowserInspectorPipe(std::unique_ptr<InspectorBrowserAgentClient> client);
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.cpp b/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.cpp
new file mode 100644
index 00000000000..2d089e80978
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.cpp
@@ -0,0 +1,111 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "BrowserInspectorTargetAgent.h"
+
+#include "WebPageInspectorController.h"
+#include "WebPageProxy.h"
+#include "WebProcessPool.h"
+#include "WebProcessProxy.h"
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+#include <JavaScriptCore/InspectorTarget.h>
+
+using namespace Inspector;
+
+namespace WebKit {
+
+namespace {
+
+InspectorTarget* targetForId(const String& targetId)
+{
+    ASSERT(isMainThread());
+    for (auto* pool : WebProcessPool::allProcessPools()) {
+        for (auto& process : pool->processes()) {
+            for (auto* page : process->pages()) {
+                auto* result = page->inspectorController().findTarget(targetId);
+                if (result != nullptr)
+                    return result;
+            }
+        }
+    }
+    return nullptr;
+}
+
+}  // namespace
+
+BrowserInspectorTargetAgent::BrowserInspectorTargetAgent(BackendDispatcher& backendDispatcher)
+    : InspectorAgentBase("Target"_s)
+    , m_backendDispatcher(TargetBackendDispatcher::create(backendDispatcher, this))
+{
+}
+
+BrowserInspectorTargetAgent::~BrowserInspectorTargetAgent() = default;
+
+void BrowserInspectorTargetAgent::didCreateFrontendAndBackend(FrontendRouter*, BackendDispatcher*)
+{
+}
+
+void BrowserInspectorTargetAgent::willDestroyFrontendAndBackend(DisconnectReason)
+{
+    m_shouldPauseOnStart = false;
+}
+
+void BrowserInspectorTargetAgent::setPauseOnStart(ErrorString&, bool pauseOnStart)
+{
+    m_shouldPauseOnStart = pauseOnStart;
+}
+
+void BrowserInspectorTargetAgent::resume(ErrorString& errorString, const String& targetId)
+{
+    auto* target = targetForId(targetId);
+    if (!target) {
+        errorString = "Missing target for given targetId"_s;
+        return;
+    }
+
+    if (!target->isPaused()) {
+        errorString = "Target for given targetId is not paused"_s;
+        return;
+    }
+
+    target->resume();
+}
+
+void BrowserInspectorTargetAgent::sendMessageToTarget(ErrorString& error, const String& in_targetId, const String& in_message)
+{
+    auto* target = targetForId(in_targetId);
+    if (target == nullptr) {
+        error = "Cannot find target with provided id.";
+        return;
+    }
+    target->sendMessageToTargetBackend(in_message);
+}
+
+void BrowserInspectorTargetAgent::activate(ErrorString& error, const String& targetId)
+{
+    auto* target = targetForId(targetId);
+    if (target == nullptr) {
+        error = "Cannot find target with provided id.";
+        return;
+    }
+    target->activate(error);
+}
+
+void BrowserInspectorTargetAgent::close(ErrorString& error, const String& targetId)
+{
+    auto* target = targetForId(targetId);
+    if (target == nullptr) {
+        error = "Cannot find target with provided id.";
+        return;
+    }
+    target->close(error);
+}
+
+void BrowserInspectorTargetAgent::didCreateTarget(InspectorTarget& target)
+{
+    if (m_shouldPauseOnStart)
+        target.pause();
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.h b/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.h
new file mode 100644
index 00000000000..4dbfe313f4e
--- /dev/null
+++ b/Source/WebKit/UIProcess/BrowserInspectorTargetAgent.h
@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "config.h"
+
+#include <JavaScriptCore/InspectorAgentBase.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class InspectorTarget;
+}
+
+namespace WebKit {
+
+class BrowserInspectorTargetAgent final : public Inspector::InspectorAgentBase, public Inspector::TargetBackendDispatcherHandler {
+    WTF_MAKE_NONCOPYABLE(BrowserInspectorTargetAgent);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    explicit BrowserInspectorTargetAgent(Inspector::BackendDispatcher&);
+    ~BrowserInspectorTargetAgent() override;
+
+    // InspectorAgentBase
+    void didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*) override;
+    void willDestroyFrontendAndBackend(Inspector::DisconnectReason) override;
+
+    // TargetBackendDispatcherHandler
+    void sendMessageToTarget(Inspector::ErrorString&, const String& targetId, const String& message) final;
+    void activate(Inspector::ErrorString&, const String& targetId) override;
+    void close(Inspector::ErrorString&, const String& targetId) override;
+    void setPauseOnStart(Inspector::ErrorString&, bool pauseOnStart) override;
+    void resume(Inspector::ErrorString&, const String& in_targetId) override;
+
+    void didCreateTarget(Inspector::InspectorTarget&);
+
+private:
+    Ref<Inspector::TargetBackendDispatcher> m_backendDispatcher;
+    bool m_shouldPauseOnStart { false };
+};
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.h b/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.h
index 454c61ffdef..6de7509037b 100644
--- a/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.h
+++ b/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.h
@@ -27,6 +27,8 @@
 
 #if HAVE(APP_SSO)
 
+#include <wtf/Forward.h>
+#include <wtf/CompletionHandler.h>
 #include "SOAuthorizationSession.h"
 #include <wtf/CompletionHandler.h>
 
@@ -39,6 +41,8 @@ class NavigationAction;
 
 namespace WebKit {
 
+class WebPageProxy;
+
 // FSM: Idle => Active => Completed
 class PopUpSOAuthorizationSession final : public SOAuthorizationSession {
 public:
diff --git a/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.mm b/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.mm
index 0f18038de98..82a96677940 100644
--- a/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.mm
+++ b/Source/WebKit/UIProcess/Cocoa/SOAuthorization/PopUpSOAuthorizationSession.mm
@@ -29,6 +29,7 @@
 #if HAVE(APP_SSO)
 
 #import "APINavigationAction.h"
+#import "WebPageProxy.h"
 #import "WKNavigationDelegatePrivate.h"
 #import "WKUIDelegate.h"
 #import "WKWebViewConfigurationPrivate.h"
diff --git a/Source/WebKit/UIProcess/Cocoa/UIDelegate.h b/Source/WebKit/UIProcess/Cocoa/UIDelegate.h
index c9498f99107..d9ab65cc0d3 100644
--- a/Source/WebKit/UIProcess/Cocoa/UIDelegate.h
+++ b/Source/WebKit/UIProcess/Cocoa/UIDelegate.h
@@ -91,6 +91,7 @@ private:
         void runJavaScriptAlert(WebPageProxy&, const WTF::String&, WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void()>&& completionHandler) final;
         void runJavaScriptConfirm(WebPageProxy&, const WTF::String&, WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void(bool)>&& completionHandler) final;
         void runJavaScriptPrompt(WebPageProxy&, const WTF::String&, const WTF::String&, WebFrameProxy*, WebCore::SecurityOriginData&&, Function<void(const WTF::String&)>&&) final;
+        void handleJavaScriptDialog(WebKit::WebPageProxy&, bool accept, const WTF::String&) final;
         void presentStorageAccessConfirmDialog(const WTF::String& requestingDomain, const WTF::String& currentDomain, CompletionHandler<void(bool)>&&);
         void requestStorageAccessConfirm(WebPageProxy&, WebFrameProxy*, const WebCore::RegistrableDomain& requestingDomain, const WebCore::RegistrableDomain& currentDomain, CompletionHandler<void(bool)>&&) final;
         void decidePolicyForGeolocationPermissionRequest(WebPageProxy&, WebFrameProxy&, API::SecurityOrigin&, Function<void(bool)>&) final;
@@ -171,6 +172,7 @@ private:
         bool webViewRunJavaScriptAlertPanelWithMessageInitiatedByFrameCompletionHandler : 1;
         bool webViewRunJavaScriptConfirmPanelWithMessageInitiatedByFrameCompletionHandler : 1;
         bool webViewRunJavaScriptTextInputPanelWithPromptDefaultTextInitiatedByFrameCompletionHandler : 1;
+        bool webViewHandleJavaScriptDialogValue : 1;
         bool webViewRequestStorageAccessPanelUnderFirstPartyCompletionHandler : 1;
         bool webViewRunBeforeUnloadConfirmPanelWithMessageInitiatedByFrameCompletionHandler : 1;
         bool webViewRequestGeolocationPermissionForFrameDecisionHandler : 1;
diff --git a/Source/WebKit/UIProcess/Cocoa/UIDelegate.mm b/Source/WebKit/UIProcess/Cocoa/UIDelegate.mm
index f9181865734..81c9f62c489 100644
--- a/Source/WebKit/UIProcess/Cocoa/UIDelegate.mm
+++ b/Source/WebKit/UIProcess/Cocoa/UIDelegate.mm
@@ -104,6 +104,7 @@ void UIDelegate::setDelegate(id <WKUIDelegate> delegate)
     m_delegateMethods.webViewRunJavaScriptAlertPanelWithMessageInitiatedByFrameCompletionHandler = [delegate respondsToSelector:@selector(webView:runJavaScriptAlertPanelWithMessage:initiatedByFrame:completionHandler:)];
     m_delegateMethods.webViewRunJavaScriptConfirmPanelWithMessageInitiatedByFrameCompletionHandler = [delegate respondsToSelector:@selector(webView:runJavaScriptConfirmPanelWithMessage:initiatedByFrame:completionHandler:)];
     m_delegateMethods.webViewRunJavaScriptTextInputPanelWithPromptDefaultTextInitiatedByFrameCompletionHandler = [delegate respondsToSelector:@selector(webView:runJavaScriptTextInputPanelWithPrompt:defaultText:initiatedByFrame:completionHandler:)];
+    m_delegateMethods.webViewHandleJavaScriptDialogValue = [delegate respondsToSelector:@selector(webView:handleJavaScriptDialog:value:)];
     m_delegateMethods.webViewRequestStorageAccessPanelUnderFirstPartyCompletionHandler = [delegate respondsToSelector:@selector(_webView:requestStorageAccessPanelForDomain:underCurrentDomain:completionHandler:)];
     m_delegateMethods.webViewRunBeforeUnloadConfirmPanelWithMessageInitiatedByFrameCompletionHandler = [delegate respondsToSelector:@selector(_webView:runBeforeUnloadConfirmPanelWithMessage:initiatedByFrame:completionHandler:)];
     m_delegateMethods.webViewRequestGeolocationPermissionForFrameDecisionHandler = [delegate respondsToSelector:@selector(_webView:requestGeolocationPermissionForFrame:decisionHandler:)];
@@ -341,6 +342,15 @@ void UIDelegate::UIClient::runJavaScriptPrompt(WebPageProxy&, const WTF::String&
     }).get()];
 }
 
+void UIDelegate::UIClient::handleJavaScriptDialog(WebKit::WebPageProxy&, bool accept, const WTF::String& value) {
+    if (!m_uiDelegate.m_delegateMethods.webViewHandleJavaScriptDialogValue)
+        return;
+    auto delegate = m_uiDelegate.m_delegate.get();
+    if (!delegate)
+        return;
+    [delegate webView:m_uiDelegate.m_webView handleJavaScriptDialog:accept value:value];
+}
+
 void UIDelegate::UIClient::requestStorageAccessConfirm(WebPageProxy&, WebFrameProxy*, const WebCore::RegistrableDomain& requestingDomain, const WebCore::RegistrableDomain& currentDomain, CompletionHandler<void(bool)>&& completionHandler)
 {
     auto delegate = m_uiDelegate.m_delegate.get();
diff --git a/Source/WebKit/UIProcess/Cocoa/WebProcessPoolCocoa.mm b/Source/WebKit/UIProcess/Cocoa/WebProcessPoolCocoa.mm
index bd3657bb087..f8fa8e3db22 100644
--- a/Source/WebKit/UIProcess/Cocoa/WebProcessPoolCocoa.mm
+++ b/Source/WebKit/UIProcess/Cocoa/WebProcessPoolCocoa.mm
@@ -121,6 +121,13 @@ static void registerUserDefaultsIfNeeded()
     [[NSUserDefaults standardUserDefaults] registerDefaults:registrationDictionary];
 }
 
+void WebProcessPool::setIgnoreTLSErrors(bool ignoreTLSErrors)
+{
+    m_ignoreTLSErrors = ignoreTLSErrors;
+    if (m_networkProcess)
+        m_networkProcess->send(Messages::NetworkProcess::SetIgnoreTLSErrors(m_ignoreTLSErrors), 0);
+}
+
 void WebProcessPool::updateProcessSuppressionState()
 {
     if (m_networkProcess)
@@ -346,6 +353,7 @@ void WebProcessPool::platformInitializeNetworkProcess(NetworkProcessCreationPara
         }
     }
 
+    parameters.ignoreTLSErrors = m_ignoreTLSErrors;
     parameters.enableLegacyTLS = false;
     if (id value = [defaults objectForKey:@"WebKitEnableLegacyTLS"])
         parameters.enableLegacyTLS = [value boolValue];
diff --git a/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp b/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp
index 9693809e34e..b45a4e7aa61 100644
--- a/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp
+++ b/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.cpp
@@ -37,6 +37,7 @@
 #include "WebProcessProxy.h"
 #include <WebCore/PlatformDisplay.h>
 #include <WebCore/Region.h>
+#include <wtf/Vector.h>
 
 #if PLATFORM(GTK)
 #include <gtk/gtk.h>
@@ -133,6 +134,11 @@ void DrawingAreaProxyCoordinatedGraphics::deviceScaleFactorDidChange()
     backingStoreStateDidChange(RespondImmediately);
 }
 
+void DrawingAreaProxyCoordinatedGraphics::waitForBackingStoreUpdate(Function<void ()>&& callback)
+{
+    m_callbacks.set(m_currentBackingStoreStateID, WTFMove(callback));
+}
+
 void DrawingAreaProxyCoordinatedGraphics::waitForBackingStoreUpdateOnNextPaint()
 {
     m_hasReceivedFirstUpdate = true;
@@ -195,6 +201,16 @@ void DrawingAreaProxyCoordinatedGraphics::didUpdateBackingStoreState(uint64_t ba
     else
         m_hasReceivedFirstUpdate = true;
 
+    Vector<uint64_t> notified;
+    for (auto& [key, value] : m_callbacks) {
+        if (backingStoreStateID > key) {
+            notified.append(key);
+            value();
+        }
+    }
+    for (uint64_t id : notified)
+        m_callbacks.remove(id);
+
 #if !PLATFORM(WPE)
     if (isInAcceleratedCompositingMode()) {
         ASSERT(!m_backingStore);
diff --git a/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h b/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h
index d7695088e7c..4fe533572b6 100644
--- a/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h
+++ b/Source/WebKit/UIProcess/CoordinatedGraphics/DrawingAreaProxyCoordinatedGraphics.h
@@ -30,6 +30,7 @@
 #include "BackingStore.h"
 #include "DrawingAreaProxy.h"
 #include "LayerTreeContext.h"
+#include <wtf/HashMap.h>
 #include <wtf/RunLoop.h>
 
 namespace WebCore {
@@ -49,6 +50,7 @@ public:
 
     bool isInAcceleratedCompositingMode() const { return !m_layerTreeContext.isEmpty(); }
     const LayerTreeContext& layerTreeContext() const { return m_layerTreeContext; }
+    void waitForBackingStoreUpdate(Function<void ()>&&);
 
 private:
     // DrawingAreaProxy
@@ -126,6 +128,8 @@ private:
     // For a new Drawing Area don't draw anything until the WebProcess has sent over the first content.
     bool m_hasReceivedFirstUpdate { false };
 
+    HashMap<uint64_t, Function<void ()>> m_callbacks;
+
 #if !PLATFORM(WPE)
     bool m_isBackingStoreDiscardable { true };
     std::unique_ptr<BackingStore> m_backingStore;
diff --git a/Source/WebKit/UIProcess/InspectorBrowserAgent.cpp b/Source/WebKit/UIProcess/InspectorBrowserAgent.cpp
new file mode 100644
index 00000000000..e0474a86aed
--- /dev/null
+++ b/Source/WebKit/UIProcess/InspectorBrowserAgent.cpp
@@ -0,0 +1,263 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "InspectorBrowserAgent.h"
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "InspectorBrowserAgentClient.h"
+#include "NetworkProcessMessages.h"
+#include "NetworkProcessProxy.h"
+#include "WebPageInspectorTarget.h"
+#include "WebPageProxy.h"
+#include "WebProcessPool.h"
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+#include <pal/SessionID.h>
+#include <wtf/HashMap.h>
+#include <wtf/HexNumber.h>
+
+
+using namespace Inspector;
+
+namespace WebKit {
+
+namespace {
+
+Inspector::Protocol::Browser::CookieSameSitePolicy cookieSameSitePolicy(WebCore::Cookie::SameSitePolicy policy)
+{
+    switch (policy) {
+    case WebCore::Cookie::SameSitePolicy::None:
+        return Inspector::Protocol::Browser::CookieSameSitePolicy::None;
+    case WebCore::Cookie::SameSitePolicy::Lax:
+        return Inspector::Protocol::Browser::CookieSameSitePolicy::Lax;
+    case WebCore::Cookie::SameSitePolicy::Strict:
+        return Inspector::Protocol::Browser::CookieSameSitePolicy::Strict;
+    }
+    ASSERT_NOT_REACHED();
+    return Inspector::Protocol::Browser::CookieSameSitePolicy::None;
+}
+
+Ref<Inspector::Protocol::Browser::Cookie> buildObjectForCookie(const WebCore::Cookie& cookie)
+{
+    return Inspector::Protocol::Browser::Cookie::create()
+        .setName(cookie.name)
+        .setValue(cookie.value)
+        .setDomain(cookie.domain)
+        .setPath(cookie.path)
+        .setExpires(cookie.expires)
+        .setHttpOnly(cookie.httpOnly)
+        .setSecure(cookie.secure)
+        .setSession(cookie.session)
+        .setSameSite(cookieSameSitePolicy(cookie.sameSite))
+        .release();
+}
+
+}  // namespace
+
+InspectorBrowserAgent::InspectorBrowserAgent(Inspector::BackendDispatcher& backendDispatcher, InspectorBrowserAgentClient* client)
+    : InspectorAgentBase("Browser"_s)
+    , m_backendDispatcher(BrowserBackendDispatcher::create(backendDispatcher, this))
+    , m_client(client)
+{
+}
+
+InspectorBrowserAgent::~InspectorBrowserAgent() = default;
+
+void InspectorBrowserAgent::didCreateFrontendAndBackend(FrontendRouter*, BackendDispatcher*)
+{
+}
+
+void InspectorBrowserAgent::willDestroyFrontendAndBackend(DisconnectReason)
+{
+}
+
+void InspectorBrowserAgent::close(ErrorString& errorString)
+{
+    if (m_client == nullptr) {
+        errorString = "no platform delegate to close browser";
+    } else {
+        m_client->closeAllWindows();
+    }
+}
+
+void InspectorBrowserAgent::createContext(ErrorString& errorString, String* browserContextID)
+{
+    BrowserContext browserContext = m_client->createBrowserContext(errorString);
+    if (!errorString.isEmpty())
+        return;
+    browserContext.processPool->setPrimaryDataStore(*browserContext.dataStore);
+    browserContext.processPool->ensureNetworkProcess(browserContext.dataStore.get());
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+    *browserContextID = toBrowserContextIDProtocolString(sessionID);
+    m_browserContexts.set(*browserContextID, browserContext);
+}
+
+void InspectorBrowserAgent::deleteContext(ErrorString& errorString, const String& browserContextID)
+{
+    BrowserContext browserContext = lookupBrowserContext(errorString, &browserContextID);
+    if (!errorString.isEmpty())
+        return;
+
+    Vector<WebPageProxy*> pages;
+    for (auto& process : browserContext.processPool->processes()) {
+        for (auto* page : process->pages())
+            pages.append(page);
+    }
+
+    for (auto* page : pages)
+        page->closePage();
+
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+    m_client->deleteBrowserContext(errorString, sessionID);
+    m_browserContexts.remove(browserContextID);
+}
+
+void InspectorBrowserAgent::createPage(ErrorString& errorString, const String* browserContextID, String* targetID)
+{
+    BrowserContext browserContext = lookupBrowserContext(errorString, browserContextID);
+    if (!errorString.isEmpty())
+        return;
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+    RefPtr<WebPageProxy> page = m_client->createPage(errorString, sessionID);
+    if (page == nullptr)
+        return;
+    *targetID = WebPageInspectorTarget::toTargetID(page->webPageID());
+}
+
+void InspectorBrowserAgent::setIgnoreCertificateErrors(Inspector::ErrorString& errorString, const String* browserContextID, bool ignore)
+{
+    BrowserContext browserContext = lookupBrowserContext(errorString, browserContextID);
+    if (!errorString.isEmpty())
+        return;
+    browserContext.processPool->setIgnoreTLSErrors(ignore);
+}
+
+void InspectorBrowserAgent::getAllCookies(const String* browserContextID, Ref<GetAllCookiesCallback>&& callback) {
+    String errorString;
+    BrowserContext browserContext = lookupBrowserContext(errorString, browserContextID);
+    if (!errorString.isEmpty()) {
+        callback->sendFailure(errorString);
+        return;
+    }
+
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+    NetworkProcessProxy* networkProcess = browserContext.processPool->networkProcess();
+    networkProcess->sendWithAsyncReply(Messages::NetworkProcess::GetAllCookies(sessionID),
+        [callback = WTFMove(callback)](Vector<WebCore::Cookie> allCookies) {
+            if (!callback->isActive())
+                return;
+            auto cookies = JSON::ArrayOf<Inspector::Protocol::Browser::Cookie>::create();
+            for (const auto& cookie : allCookies)
+                cookies->addItem(buildObjectForCookie(cookie));
+            callback->sendSuccess(WTFMove(cookies));
+        }, 0);
+}
+
+void InspectorBrowserAgent::setCookies(const String* browserContextID, const JSON::Array& in_cookies, Ref<SetCookiesCallback>&& callback) {
+    String errorString;
+    BrowserContext browserContext = lookupBrowserContext(errorString, browserContextID);
+    if (!errorString.isEmpty()) {
+        callback->sendFailure(errorString);
+        return;
+    }
+
+    NetworkProcessProxy* networkProcess = browserContext.processPool->networkProcess();
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+
+    Vector<WebCore::Cookie> cookies;
+    for (unsigned i = 0; i < in_cookies.length(); ++i) {
+        RefPtr<JSON::Value> item = in_cookies.get(i);
+        RefPtr<JSON::Object> obj;
+        if (!item->asObject(obj)) {
+            errorString = "Invalid cookie payload format"_s;
+            return;
+        }
+
+        WebCore::Cookie cookie;
+        if (!obj->getString("name", cookie.name) ||
+            !obj->getString("value", cookie.value) ||
+            !obj->getString("domain", cookie.domain) ||
+            !obj->getString("path", cookie.path)) {
+            errorString = "Invalid file payload format"_s;
+            return;
+        }
+
+        obj->getDouble("expires", cookie.expires);
+        obj->getBoolean("httpOnly", cookie.httpOnly);
+        obj->getBoolean("secure", cookie.secure);
+        obj->getBoolean("session", cookie.session);
+        String sameSite;
+        if (obj->getString("sameSite", sameSite)) {
+            if (sameSite == "None")
+                cookie.sameSite = WebCore::Cookie::SameSitePolicy::None;
+            if (sameSite == "Lax")
+                cookie.sameSite = WebCore::Cookie::SameSitePolicy::Lax;
+            if (sameSite == "Strict")
+                cookie.sameSite = WebCore::Cookie::SameSitePolicy::Strict;
+        }
+        cookies.append(WTFMove(cookie));
+    }
+
+    networkProcess->sendWithAsyncReply(Messages::NetworkProcess::SetCookies(sessionID, WTFMove(cookies)),
+        [callback = WTFMove(callback)](bool success) {
+            if (!callback->isActive())
+                return;
+
+            if (success)
+                callback->sendSuccess();
+            else
+                callback->sendFailure("Internal error: no network storage"_s);
+            callback->sendSuccess();
+        }, 0);
+}
+
+void InspectorBrowserAgent::deleteAllCookies(const String* browserContextID, Ref<DeleteAllCookiesCallback>&& callback) {
+    String errorString;
+    BrowserContext browserContext = lookupBrowserContext(errorString, browserContextID);
+    if (!errorString.isEmpty()) {
+        callback->sendFailure(errorString);
+        return;
+    }
+
+    NetworkProcessProxy* networkProcess = browserContext.processPool->networkProcess();
+    PAL::SessionID sessionID = browserContext.dataStore->sessionID();
+    networkProcess->sendWithAsyncReply(Messages::NetworkProcess::DeleteAllCookies(sessionID),
+        [callback = WTFMove(callback)](bool success) {
+            if (!callback->isActive())
+                return;
+            if (success)
+                callback->sendSuccess();
+            else
+                callback->sendFailure("Internal error: no network storage"_s);
+        }, 0);
+}
+
+String InspectorBrowserAgent::toBrowserContextIDProtocolString(const PAL::SessionID& sessionID)
+{
+    StringBuilder builder;
+    appendUnsignedAsHexFixedSize(sessionID.toUInt64(), builder, 16);
+    return builder.toString();
+}
+
+BrowserContext InspectorBrowserAgent::lookupBrowserContext(ErrorString& errorString, const String* browserContextID) {
+    if (!browserContextID) {
+        for (auto& pool : WebProcessPool::allProcessPools()) {
+            BrowserContext context;
+            context.processPool = pool;
+            context.dataStore = pool->websiteDataStore();
+            return context;
+        }
+        errorString = "No default context"_s;
+        return BrowserContext();
+    }
+
+    BrowserContext browserContext = m_browserContexts.get(*browserContextID);
+    if (!browserContext.processPool)
+        errorString = "Could not find browser context for given id"_s;
+    return browserContext;
+}
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/InspectorBrowserAgent.h b/Source/WebKit/UIProcess/InspectorBrowserAgent.h
new file mode 100644
index 00000000000..5f11df16618
--- /dev/null
+++ b/Source/WebKit/UIProcess/InspectorBrowserAgent.h
@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "InspectorBrowserAgentClient.h"
+#include <JavaScriptCore/InspectorAgentBase.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+#include <wtf/HashMap.h>
+#include <pal/SessionID.h>
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class BackendDispatcher;
+class FrontendChannel;
+class FrontendRouter;
+}
+
+namespace PAL {
+class SessionID;
+}
+
+namespace WebKit {
+
+class NetworkProcess;
+class WebProcessPool;
+
+class InspectorBrowserAgent final : public Inspector::InspectorAgentBase, public Inspector::BrowserBackendDispatcherHandler {
+    WTF_MAKE_NONCOPYABLE(InspectorBrowserAgent);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    InspectorBrowserAgent(Inspector::BackendDispatcher&, InspectorBrowserAgentClient*);
+    ~InspectorBrowserAgent() override;
+
+    // InspectorAgentBase
+    void didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*) override;
+    void willDestroyFrontendAndBackend(Inspector::DisconnectReason) override;
+
+    // BrowserBackendDispatcherHandler
+    void close(Inspector::ErrorString&) override;
+    void createContext(Inspector::ErrorString&, String* browserContextID) override;
+    void deleteContext(Inspector::ErrorString&, const String& browserContextID) override;
+    void createPage(Inspector::ErrorString&, const String* browserContextID, String* targetId) override;
+    void setIgnoreCertificateErrors(Inspector::ErrorString&, const String* browserContextID, bool ignore) override;
+
+    void getAllCookies(const String* browserContextID, Ref<GetAllCookiesCallback>&&) override;
+    void setCookies(const String* browserContextID, const JSON::Array& in_cookies, Ref<SetCookiesCallback>&&) override;
+    void deleteAllCookies(const String* browserContextID, Ref<DeleteAllCookiesCallback>&&) override;
+
+    static String toBrowserContextIDProtocolString(const PAL::SessionID&);
+
+private:
+    BrowserContext lookupBrowserContext(Inspector::ErrorString&, const String* browserContextID);
+    Ref<Inspector::BrowserBackendDispatcher> m_backendDispatcher;
+    InspectorBrowserAgentClient* m_client;
+    HashMap<String, BrowserContext> m_browserContexts;
+};
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/InspectorBrowserAgentClient.h b/Source/WebKit/UIProcess/InspectorBrowserAgentClient.h
new file mode 100644
index 00000000000..866db590d59
--- /dev/null
+++ b/Source/WebKit/UIProcess/InspectorBrowserAgentClient.h
@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include <pal/SessionID.h>
+#include <wtf/Forward.h>
+
+namespace WebKit {
+
+class WebsiteDataStore;
+class WebPageProxy;
+class WebProcessPool;
+
+struct BrowserContext {
+    RefPtr<WebsiteDataStore> dataStore;
+    RefPtr<WebProcessPool> processPool;
+};
+
+class InspectorBrowserAgentClient {
+public:
+    virtual ~InspectorBrowserAgentClient() = default;
+    virtual RefPtr<WebKit::WebPageProxy> createPage(WTF::String& error, PAL::SessionID) = 0;
+    virtual void closeAllWindows() = 0;
+    virtual BrowserContext createBrowserContext(WTF::String& error) = 0;
+    virtual void deleteBrowserContext(WTF::String& error, PAL::SessionID) = 0;
+};
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/InspectorDialogAgent.cpp b/Source/WebKit/UIProcess/InspectorDialogAgent.cpp
new file mode 100644
index 00000000000..121b5969d4a
--- /dev/null
+++ b/Source/WebKit/UIProcess/InspectorDialogAgent.cpp
@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "InspectorDialogAgent.h"
+
+#include "APINavigation.h"
+#include "APIUIClient.h"
+#include "WebPageProxy.h"
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+
+
+namespace WebKit {
+
+using namespace Inspector;
+
+InspectorDialogAgent::InspectorDialogAgent(Inspector::BackendDispatcher& backendDispatcher, Inspector::FrontendRouter& frontendRouter, WebPageProxy& page)
+    : InspectorAgentBase("Dialog"_s)
+    , m_frontendDispatcher(makeUnique<DialogFrontendDispatcher>(frontendRouter))
+    , m_backendDispatcher(DialogBackendDispatcher::create(backendDispatcher, this))
+    , m_page(page)
+{
+}
+
+InspectorDialogAgent::~InspectorDialogAgent()
+{
+    Inspector::ErrorString err;
+    disable(err);
+}
+
+void InspectorDialogAgent::didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*)
+{
+}
+
+void InspectorDialogAgent::willDestroyFrontendAndBackend(Inspector::DisconnectReason)
+{
+}
+
+void InspectorDialogAgent::enable(Inspector::ErrorString& errorString)
+{
+    if (m_page.inspectorDialogAgent()) {
+        errorString = "Dialog domain is already enabled."_s;
+        return;
+    }
+    m_page.setInspectorDialogAgent(this);
+}
+
+void InspectorDialogAgent::disable(Inspector::ErrorString&)
+{
+    if (m_page.inspectorDialogAgent() != this)
+        return;
+    m_page.setInspectorDialogAgent(nullptr);
+}
+
+void InspectorDialogAgent::handleJavaScriptDialog(Inspector::ErrorString& errorString, bool accept, const String* value)
+{
+    m_page.uiClient().handleJavaScriptDialog(m_page, accept, value ? *value : String());
+}
+
+void InspectorDialogAgent::javascriptDialogOpening(const String& type, const String& message, const String* defaultValue) {
+    m_frontendDispatcher->javascriptDialogOpening(type, message, defaultValue);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/InspectorDialogAgent.h b/Source/WebKit/UIProcess/InspectorDialogAgent.h
new file mode 100644
index 00000000000..203c203a0e2
--- /dev/null
+++ b/Source/WebKit/UIProcess/InspectorDialogAgent.h
@@ -0,0 +1,48 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "WebEvent.h"
+
+#include <JavaScriptCore/InspectorAgentBase.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+#include <JavaScriptCore/InspectorFrontendDispatchers.h>
+
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class FrontendChannel;
+class FrontendRouter;
+}
+
+namespace WebKit {
+
+class NativeWebKeyboardEvent;
+class WebPageProxy;
+
+class InspectorDialogAgent : public Inspector::InspectorAgentBase, public Inspector::DialogBackendDispatcherHandler {
+    WTF_MAKE_NONCOPYABLE(InspectorDialogAgent);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    InspectorDialogAgent(Inspector::BackendDispatcher& backendDispatcher, Inspector::FrontendRouter& frontendRouter, WebPageProxy& page);
+    ~InspectorDialogAgent() override;
+
+    void didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*) override;
+    void willDestroyFrontendAndBackend(Inspector::DisconnectReason) override;
+
+    void enable(Inspector::ErrorString&) override;
+    void disable(Inspector::ErrorString&) override;
+    void handleJavaScriptDialog(Inspector::ErrorString& errorString, bool accept, const String* promptText) override;
+
+    void javascriptDialogOpening(const String& type, const String& message, const String* defaultValue = nullptr);
+
+private:
+    void platformHandleJavaScriptDialog(bool accept, const String* promptText);
+    std::unique_ptr<Inspector::DialogFrontendDispatcher> m_frontendDispatcher;
+    Ref<Inspector::DialogBackendDispatcher> m_backendDispatcher;
+    WebPageProxy& m_page;
+};
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/InspectorTargetProxy.cpp b/Source/WebKit/UIProcess/InspectorTargetProxy.cpp
index 6928ca2fbfb..a80eef613f4 100644
--- a/Source/WebKit/UIProcess/InspectorTargetProxy.cpp
+++ b/Source/WebKit/UIProcess/InspectorTargetProxy.cpp
@@ -26,12 +26,15 @@
 #include "config.h"
 #include "InspectorTargetProxy.h"
 
+#include "APIPageConfiguration.h"
 #include "ProvisionalPageProxy.h"
 #include "WebFrameProxy.h"
 #include "WebPageInspectorTarget.h"
 #include "WebPageMessages.h"
 #include "WebPageProxy.h"
 #include "WebProcessProxy.h"
+#include "ProvisionalPageProxy.h"
+
 
 namespace WebKit {
 
@@ -39,23 +42,29 @@ using namespace Inspector;
 
 std::unique_ptr<InspectorTargetProxy> InspectorTargetProxy::create(WebPageProxy& page, const String& targetId, Inspector::InspectorTargetType type)
 {
-    return makeUnique<InspectorTargetProxy>(page, targetId, type);
+    return makeUnique<InspectorTargetProxy>(page, nullptr, targetId, type);
 }
 
 std::unique_ptr<InspectorTargetProxy> InspectorTargetProxy::create(ProvisionalPageProxy& provisionalPage, const String& targetId, Inspector::InspectorTargetType type)
 {
-    auto target = InspectorTargetProxy::create(provisionalPage.page(), targetId, type);
-    target->m_provisionalPage = makeWeakPtr(provisionalPage);
-    return target;
+    return makeUnique<InspectorTargetProxy>(provisionalPage.page(), &provisionalPage, targetId, type);
 }
 
-InspectorTargetProxy::InspectorTargetProxy(WebPageProxy& page, const String& targetId, Inspector::InspectorTargetType type)
+InspectorTargetProxy::InspectorTargetProxy(WebPageProxy& page, ProvisionalPageProxy* provisionalPage, const String& targetId, Inspector::InspectorTargetType type)
     : m_page(page)
+    , m_provisionalPage(makeWeakPtr(provisionalPage))
     , m_identifier(targetId)
     , m_type(type)
 {
 }
 
+String InspectorTargetProxy::url() const
+{
+    if (m_page.provisionalPageProxy())
+        return m_page.provisionalPageProxy()->provisionalURL().string();
+    return m_page.pageLoadState().activeURL();
+}
+
 void InspectorTargetProxy::connect(Inspector::FrontendChannel::ConnectionType connectionType)
 {
     if (m_provisionalPage) {
@@ -102,4 +111,19 @@ bool InspectorTargetProxy::isProvisional() const
     return !!m_provisionalPage;
 }
 
+String InspectorTargetProxy::oldTargetID() const
+{
+    if (!m_provisionalPage)
+        return String();
+    return WebPageInspectorTarget::toTargetID(m_page.webPageID());
+}
+
+String InspectorTargetProxy::openerID() const
+{
+    auto* opener = m_page.configuration().relatedPage();
+    if (!opener)
+        return String();
+    return WebPageInspectorTarget::toTargetID(opener->webPageID());
+}
+
 } // namespace WebKit
diff --git a/Source/WebKit/UIProcess/InspectorTargetProxy.h b/Source/WebKit/UIProcess/InspectorTargetProxy.h
index a2239cec8e1..3985edf2081 100644
--- a/Source/WebKit/UIProcess/InspectorTargetProxy.h
+++ b/Source/WebKit/UIProcess/InspectorTargetProxy.h
@@ -37,30 +37,35 @@ class WebPageProxy;
 // NOTE: This UIProcess side InspectorTarget doesn't care about the frontend channel, since
 // any target -> frontend messages will be routed to the WebPageProxy with a targetId.
 
-class InspectorTargetProxy final : public Inspector::InspectorTarget {
+class InspectorTargetProxy : public Inspector::InspectorTarget {
     WTF_MAKE_FAST_ALLOCATED;
     WTF_MAKE_NONCOPYABLE(InspectorTargetProxy);
 public:
     static std::unique_ptr<InspectorTargetProxy> create(WebPageProxy&, const String& targetId, Inspector::InspectorTargetType);
     static std::unique_ptr<InspectorTargetProxy> create(ProvisionalPageProxy&, const String& targetId, Inspector::InspectorTargetType);
-    InspectorTargetProxy(WebPageProxy&, const String& targetId, Inspector::InspectorTargetType);
+    InspectorTargetProxy(WebPageProxy&, ProvisionalPageProxy*, const String& targetId, Inspector::InspectorTargetType);
     ~InspectorTargetProxy() = default;
 
     Inspector::InspectorTargetType type() const final { return m_type; }
     String identifier() const final { return m_identifier; }
+    String url() const final;
 
     void didCommitProvisionalTarget();
     bool isProvisional() const override;
+    String oldTargetID() const override;
+    String openerID() const override;
 
     void connect(Inspector::FrontendChannel::ConnectionType) override;
     void disconnect() override;
     void sendMessageToTargetBackend(const String&) override;
 
-private:
+protected:
     WebPageProxy& m_page;
+
+private:
+    WeakPtr<ProvisionalPageProxy> m_provisionalPage;
     String m_identifier;
     Inspector::InspectorTargetType m_type;
-    WeakPtr<ProvisionalPageProxy> m_provisionalPage;
 };
 
 } // namespace WebKit
diff --git a/Source/WebKit/UIProcess/RemoteInspectorPipe.cpp b/Source/WebKit/UIProcess/RemoteInspectorPipe.cpp
new file mode 100644
index 00000000000..a3a3bb02dcd
--- /dev/null
+++ b/Source/WebKit/UIProcess/RemoteInspectorPipe.cpp
@@ -0,0 +1,132 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "RemoteInspectorPipe.h"
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "BrowserInspectorController.h"
+#include <JavaScriptCore/InspectorFrontendChannel.h>
+#include <wtf/MainThread.h>
+#include <wtf/RunLoop.h>
+#include <wtf/UniqueArray.h>
+#include <wtf/Vector.h>
+#include <wtf/WorkQueue.h>
+
+#if OS(UNIX)
+#include <stdio.h>
+#include <unistd.h>
+#endif
+
+namespace WebKit {
+
+static const int readFD = 3;
+static const int writeFD = 4;
+
+class RemoteInspectorPipe::RemoteFrontendChannel : public Inspector::FrontendChannel {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    RemoteFrontendChannel()
+        : m_senderQueue(WorkQueue::create("Inspector pipe writer"))
+    {
+    }
+
+    ~RemoteFrontendChannel() override = default;
+
+    ConnectionType connectionType() const override
+    {
+        return ConnectionType::Remote;
+    }
+
+    void sendMessageToFrontend(const String& message) override
+    {
+        m_senderQueue->dispatch([message = message.isolatedCopy()]() {
+            dprintf(writeFD, "%s%c", message.ascii().data(), '\0');
+        });
+    }
+
+private:
+    Ref<WorkQueue> m_senderQueue;
+};
+
+RemoteInspectorPipe::RemoteInspectorPipe(BrowserInspectorController& browserInspectorController)
+    : m_remoteFrontendChannel(makeUnique<RemoteFrontendChannel>())
+    , m_browserInspectorController(browserInspectorController)
+{
+    start();
+}
+
+RemoteInspectorPipe::~RemoteInspectorPipe()
+{
+    stop();
+}
+
+bool RemoteInspectorPipe::start()
+{
+    if (m_receiverThread)
+        return true;
+
+    m_browserInspectorController.connectFrontend(*m_remoteFrontendChannel);
+    m_terminated = false;
+    m_receiverThread = Thread::create("Inspector pipe reader", [this] {
+        workerRun();
+    });
+    return true;
+}
+
+void RemoteInspectorPipe::stop()
+{
+    if (!m_receiverThread)
+        return;
+
+    m_browserInspectorController.disconnectFrontend();
+
+    m_terminated = true;
+    m_receiverThread->waitForCompletion();
+    m_receiverThread = nullptr;
+}
+
+void RemoteInspectorPipe::workerRun()
+{
+    const size_t bufSize = 256 * 1024;
+    auto buffer = makeUniqueArray<char>(bufSize);
+    Vector<char> line;
+    while (!m_terminated) {
+        ssize_t size = read(readFD, buffer.get(), bufSize);
+        if (size == 0) {
+            break;
+        }
+        if (size < 0) {
+            break;
+        }
+        size_t start = 0;
+        size_t end = line.size();
+        line.append(buffer.get(), size);
+        while (true) {
+            for (; end < line.size(); ++end) {
+                if (line[end] == '\0')
+                    break;
+            }
+            if (end == line.size())
+                break;
+
+            if (end > start) {
+                String message = String::fromUTF8(line.data() + start, end - start);
+                RunLoop::main().dispatch([this, message] {
+                    if (!m_terminated)
+                        m_browserInspectorController.dispatchMessageFromFrontend(message);
+                });
+            }
+            ++end;
+            start = end;
+        }
+        if (start != 0 && start < line.size())
+            memmove(line.data(), line.data() + start, line.size() - start);
+        line.shrink(line.size() - start);
+    }
+}
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/RemoteInspectorPipe.h b/Source/WebKit/UIProcess/RemoteInspectorPipe.h
new file mode 100644
index 00000000000..426eb17d012
--- /dev/null
+++ b/Source/WebKit/UIProcess/RemoteInspectorPipe.h
@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include <wtf/Ref.h>
+#include <wtf/RefPtr.h>
+#include <wtf/Threading.h>
+
+namespace Inspector {
+class FrontendChannel;
+}
+
+namespace WebKit {
+
+class BrowserInspectorController;
+
+class RemoteInspectorPipe {
+    WTF_MAKE_NONCOPYABLE(RemoteInspectorPipe);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    explicit RemoteInspectorPipe(BrowserInspectorController&);
+    ~RemoteInspectorPipe();
+
+private:
+    class RemoteFrontendChannel;
+
+    bool start();
+    void stop();
+
+    void workerRun();
+
+    RefPtr<Thread> m_receiverThread;
+    std::atomic<bool> m_terminated { false };
+    std::unique_ptr<Inspector::FrontendChannel> m_remoteFrontendChannel;
+    BrowserInspectorController& m_browserInspectorController;
+};
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp b/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
index 6faede54764..b98b1c78312 100644
--- a/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
+++ b/Source/WebKit/UIProcess/WebAuthentication/AuthenticatorManager.cpp
@@ -35,6 +35,7 @@
 #include "NfcService.h"
 #include "WebPageProxy.h"
 #include "WebPreferencesKeys.h"
+#include "WebProcessProxy.h"
 #include <WebCore/AuthenticatorTransport.h>
 #include <WebCore/PublicKeyCredentialCreationOptions.h>
 #include <WebCore/WebAuthenticationConstants.h>
diff --git a/Source/WebKit/UIProcess/WebAuthentication/Mock/MockAuthenticatorManager.cpp b/Source/WebKit/UIProcess/WebAuthentication/Mock/MockAuthenticatorManager.cpp
index 2c4f9ddabf0..ae9e0b80708 100644
--- a/Source/WebKit/UIProcess/WebAuthentication/Mock/MockAuthenticatorManager.cpp
+++ b/Source/WebKit/UIProcess/WebAuthentication/Mock/MockAuthenticatorManager.cpp
@@ -53,9 +53,9 @@ void MockAuthenticatorManager::respondReceivedInternal(Respond&& respond)
 void MockAuthenticatorManager::filterTransports(TransportSet& transports) const
 {
     if (!m_testConfiguration.nfc)
-        transports.remove(AuthenticatorTransport::Nfc);
+        transports.remove(WebCore::AuthenticatorTransport::Nfc);
     if (!m_testConfiguration.local)
-        transports.remove(AuthenticatorTransport::Internal);
+        transports.remove(WebCore::AuthenticatorTransport::Internal);
 }
 
 } // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorController.cpp b/Source/WebKit/UIProcess/WebPageInspectorController.cpp
index 1ee28bf7163..c1c918d6e2a 100644
--- a/Source/WebKit/UIProcess/WebPageInspectorController.cpp
+++ b/Source/WebKit/UIProcess/WebPageInspectorController.cpp
@@ -26,10 +26,13 @@
 #include "config.h"
 #include "WebPageInspectorController.h"
 
+#include "InspectorBrowserAgent.h"
 #include "ProvisionalPageProxy.h"
 #include "WebFrameProxy.h"
 #include "WebPageInspectorTarget.h"
+#include "WebPageInspectorTargetProxy.h"
 #include "WebPageProxy.h"
+#include "WebPreferences.h"
 #include <JavaScriptCore/InspectorAgentBase.h>
 #include <JavaScriptCore/InspectorBackendDispatcher.h>
 #include <JavaScriptCore/InspectorBackendDispatchers.h>
@@ -46,26 +49,56 @@ static String getTargetID(const ProvisionalPageProxy& provisionalPage)
     return WebPageInspectorTarget::toTargetID(provisionalPage.webPageID());
 }
 
+WebPageInspectorControllerObserver* WebPageInspectorController::s_observer = nullptr;
+
+void WebPageInspectorController::setObserver(WebPageInspectorControllerObserver* observer)
+{
+    s_observer = observer;
+}
+
 WebPageInspectorController::WebPageInspectorController(WebPageProxy& page)
     : m_page(page)
     , m_frontendRouter(FrontendRouter::create())
     , m_backendDispatcher(BackendDispatcher::create(m_frontendRouter.copyRef()))
 {
-    auto targetAgent = makeUnique<InspectorTargetAgent>(m_frontendRouter.get(), m_backendDispatcher.get());
+    String browserContextID;
+#if ENABLE(REMOTE_INSPECTOR)
+    browserContextID = InspectorBrowserAgent::toBrowserContextIDProtocolString(page.sessionID());
+#endif
+    auto targetAgent = makeUnique<InspectorTargetAgent>(m_frontendRouter.get(), m_backendDispatcher.get(), browserContextID);
 
     m_targetAgent = targetAgent.get();
 
     m_agents.append(WTFMove(targetAgent));
+
+    if (s_observer)
+        s_observer->didCreateInspectorController(*this);
 }
 
 void WebPageInspectorController::init()
 {
+    // window.open will create page with already running process.
+    if (!m_page.hasRunningProcess())
+        return;
     String pageTargetId = WebPageInspectorTarget::toTargetID(m_page.webPageID());
     createInspectorTarget(pageTargetId, Inspector::InspectorTargetType::Page);
 }
 
+void WebPageInspectorController::didFinishAttachingToWebProcess()
+{
+    String pageTargetID = WebPageInspectorTarget::toTargetID(m_page.webPageID());
+    // Create target only after attaching to a Web Process first time. Before that
+    // we cannot event establish frontend connection.
+    if (m_targets.contains(pageTargetID))
+        return;
+    createInspectorTarget(pageTargetID, Inspector::InspectorTargetType::Page);
+}
+
 void WebPageInspectorController::pageClosed()
 {
+    String pageTargetId = WebPageInspectorTarget::toTargetID(m_page.webPageID());
+    destroyInspectorTarget(pageTargetId);
+
     disconnectAllFrontends();
 
     m_agents.discardValues();
@@ -80,6 +113,9 @@ void WebPageInspectorController::connectFrontend(Inspector::FrontendChannel& fro
 {
     bool connectingFirstFrontend = !m_frontendRouter->hasFrontends();
 
+    if (connectingFirstFrontend)
+        adjustPageSettings();
+
     m_frontendRouter->connectFrontend(frontendChannel);
 
     if (connectingFirstFrontend)
@@ -134,6 +170,16 @@ void WebPageInspectorController::dispatchMessageFromFrontend(const String& messa
     m_backendDispatcher->dispatch(message);
 }
 
+bool WebPageInspectorController::dispatchMessageToTargetBackend(const String& message)
+{
+    return m_backendDispatcher->dispatch(message, BackendDispatcher::Mode::ContinueIfDomainIsMissing) == BackendDispatcher::DispatchResult::Finished;
+}
+
+Inspector::InspectorTarget* WebPageInspectorController::findTarget(const String& targetId)
+{
+    return m_targets.get(targetId);
+}
+
 #if ENABLE(REMOTE_INSPECTOR)
 void WebPageInspectorController::setIndicating(bool indicating)
 {
@@ -150,7 +196,12 @@ void WebPageInspectorController::setIndicating(bool indicating)
 
 void WebPageInspectorController::createInspectorTarget(const String& targetId, Inspector::InspectorTargetType type)
 {
-    addTarget(InspectorTargetProxy::create(m_page, targetId, type));
+    std::unique_ptr<InspectorTargetProxy> target;
+    if (type == Inspector::InspectorTargetType::Page)
+        target = WebPageInspectorTargetProxy::create(m_page, *m_targetAgent, targetId);
+    else
+        target = InspectorTargetProxy::create(m_page, targetId, type);
+    addTarget(WTFMove(target));
 }
 
 void WebPageInspectorController::destroyInspectorTarget(const String& targetId)
@@ -186,7 +237,7 @@ void WebPageInspectorController::setContinueLoadingCallback(const ProvisionalPag
 
 void WebPageInspectorController::didCreateProvisionalPage(ProvisionalPageProxy& provisionalPage)
 {
-    addTarget(InspectorTargetProxy::create(provisionalPage, getTargetID(provisionalPage), Inspector::InspectorTargetType::Page));
+    addTarget(WebPageInspectorTargetProxy::create(provisionalPage, *m_targetAgent, getTargetID(provisionalPage)));
 }
 
 void WebPageInspectorController::willDestroyProvisionalPage(const ProvisionalPageProxy& provisionalPage)
@@ -214,8 +265,22 @@ void WebPageInspectorController::didCommitProvisionalPage(WebCore::PageIdentifie
 
 void WebPageInspectorController::addTarget(std::unique_ptr<InspectorTargetProxy>&& target)
 {
+    if (s_observer)
+        s_observer->didCreateTarget(*target);
     m_targetAgent->targetCreated(*target);
     m_targets.set(target->identifier(), WTFMove(target));
 }
 
+void WebPageInspectorController::adjustPageSettings()
+{
+    // Set this to true as otherwise updating any preferences will override its
+    // value in the Web Process to false (and InspectorController sets it locally
+    // to true when frontend is connected).
+    m_page.preferences().setDeveloperExtrasEnabled(true);
+
+    // Navigation to cached pages doesn't fire some of the events (e.g. execution context created)
+    // that inspector depends on. So we disable the cache when front-end connects.
+    m_page.preferences().setUsesBackForwardCache(false);
+}
+
 } // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorController.h b/Source/WebKit/UIProcess/WebPageInspectorController.h
index 78caedf0c0c..a380d778c36 100644
--- a/Source/WebKit/UIProcess/WebPageInspectorController.h
+++ b/Source/WebKit/UIProcess/WebPageInspectorController.h
@@ -37,10 +37,22 @@ namespace Inspector {
 class BackendDispatcher;
 class FrontendChannel;
 class FrontendRouter;
+class InspectorTarget;
 }
 
 namespace WebKit {
 
+class WebPageInspectorController;
+
+class WebPageInspectorControllerObserver {
+public:
+    virtual void didCreateInspectorController(WebPageInspectorController&) = 0;
+    virtual void didCreateTarget(Inspector::InspectorTarget&) = 0;
+
+protected:
+    virtual ~WebPageInspectorControllerObserver() = default;
+};
+
 class WebPageInspectorController {
     WTF_MAKE_NONCOPYABLE(WebPageInspectorController);
     WTF_MAKE_FAST_ALLOCATED;
@@ -48,7 +60,12 @@ public:
     WebPageInspectorController(WebPageProxy&);
 
     void init();
+    void didFinishAttachingToWebProcess();
+
+    static void setObserver(WebPageInspectorControllerObserver*);
+
     void pageClosed();
+    void didProcessAllPendingKeyboardEvents();
 
     bool hasLocalFrontend() const;
 
@@ -57,6 +74,8 @@ public:
     void disconnectAllFrontends();
 
     void dispatchMessageFromFrontend(const String& message);
+    Inspector::InspectorTarget* findTarget(const String& targetId);
+    bool dispatchMessageToTargetBackend(const String&);
 
 #if ENABLE(REMOTE_INSPECTOR)
     void setIndicating(bool);
@@ -75,6 +94,7 @@ public:
 
 private:
     void addTarget(std::unique_ptr<InspectorTargetProxy>&&);
+    void adjustPageSettings();
 
     WebPageProxy& m_page;
     Ref<Inspector::FrontendRouter> m_frontendRouter;
@@ -82,6 +102,8 @@ private:
     Inspector::AgentRegistry m_agents;
     Inspector::InspectorTargetAgent* m_targetAgent;
     HashMap<String, std::unique_ptr<InspectorTargetProxy>> m_targets;
+
+    static WebPageInspectorControllerObserver* s_observer;
 };
 
 } // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.cpp b/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.cpp
new file mode 100644
index 00000000000..c2cd2d42a63
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.cpp
@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorEmulationAgent.h"
+
+#include "WebPageProxy.h"
+#include "WebPreferences.h"
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+
+
+namespace WebKit {
+
+using namespace Inspector;
+
+WebPageInspectorEmulationAgent::WebPageInspectorEmulationAgent(BackendDispatcher& backendDispatcher, WebPageProxy& page)
+    : InspectorAgentBase("Emulation"_s)
+    , m_backendDispatcher(EmulationBackendDispatcher::create(backendDispatcher, this))
+    , m_page(page)
+{
+}
+
+WebPageInspectorEmulationAgent::~WebPageInspectorEmulationAgent()
+{
+}
+
+void WebPageInspectorEmulationAgent::didCreateFrontendAndBackend(FrontendRouter*, BackendDispatcher*)
+{
+}
+
+void WebPageInspectorEmulationAgent::willDestroyFrontendAndBackend(DisconnectReason)
+{
+}
+
+void WebPageInspectorEmulationAgent::setDeviceMetricsOverride(int width, int height, double deviceScaleFactor, Ref<SetDeviceMetricsOverrideCallback>&& callback) {
+    m_page.setCustomDeviceScaleFactor(deviceScaleFactor);
+    platformSetSize(width, height, [callback = WTFMove(callback)](const String& error) {
+        if (error.isEmpty())
+            callback->sendSuccess();
+        else
+            callback->sendFailure(error);
+    });
+}
+
+void WebPageInspectorEmulationAgent::setJavaScriptEnabled(ErrorString&, bool enabled)
+{
+    auto copy = m_page.preferences().copy();
+    copy->setJavaScriptEnabled(enabled);
+    m_page.setPreferences(copy);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.h b/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.h
new file mode 100644
index 00000000000..2047a0c3fb7
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorEmulationAgent.h
@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include <JavaScriptCore/InspectorAgentBase.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+
+#include <wtf/Forward.h>
+#include <wtf/Function.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class BackendDispatcher;
+class FrontendChannel;
+class FrontendRouter;
+}
+
+namespace WebKit {
+
+class WebPageProxy;
+
+class WebPageInspectorEmulationAgent : public Inspector::InspectorAgentBase, public Inspector::EmulationBackendDispatcherHandler {
+    WTF_MAKE_NONCOPYABLE(WebPageInspectorEmulationAgent);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    WebPageInspectorEmulationAgent(Inspector::BackendDispatcher& backendDispatcher, WebPageProxy& page);
+    ~WebPageInspectorEmulationAgent() override;
+
+    void didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*) override;
+    void willDestroyFrontendAndBackend(Inspector::DisconnectReason) override;
+
+    void setDeviceMetricsOverride(int width, int height, double deviceScaleFactor, Ref<SetDeviceMetricsOverrideCallback>&&) override;
+    void setJavaScriptEnabled(Inspector::ErrorString&, bool enabled) override;
+
+private:
+    void platformSetSize(int width, int height, Function<void (const String& error)>&&);
+
+    Ref<Inspector::EmulationBackendDispatcher> m_backendDispatcher;
+    WebPageProxy& m_page;
+};
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorInputAgent.cpp b/Source/WebKit/UIProcess/WebPageInspectorInputAgent.cpp
new file mode 100644
index 00000000000..3e834010f48
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorInputAgent.cpp
@@ -0,0 +1,250 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorInputAgent.h"
+
+#include "APINavigation.h"
+#include "NativeWebKeyboardEvent.h"
+#include "NativeWebMouseEvent.h"
+#include "WebPageProxy.h"
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+
+
+namespace WebKit {
+
+using namespace Inspector;
+
+namespace {
+
+template<class T>
+class CallbackList {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    ~CallbackList()
+    {
+        for (const auto& callback : m_callbacks)
+            callback->sendFailure("Page closed");
+    }
+
+    void append(Ref<T>&& callback)
+    {
+        m_callbacks.append(WTFMove(callback));
+    }
+
+    void sendSuccess()
+    {
+        for (const auto& callback : m_callbacks)
+            callback->sendSuccess();
+        m_callbacks.clear();
+    }
+
+private:
+    Vector<Ref<T>> m_callbacks;
+};
+
+} // namespace
+
+class WebPageInspectorInputAgent::InspectorInputObserver : public WebPageProxy::InputProcessingObserver {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    using KeyboardCallback = Inspector::InputBackendDispatcherHandler::DispatchKeyEventCallback;
+    using MouseCallback = Inspector::InputBackendDispatcherHandler::DispatchMouseEventCallback;
+
+    ~InspectorInputObserver() override = default;
+
+    void didProcessAllPendingKeyboardEvents() override
+    {
+        m_keyboardCallbacks.sendSuccess();
+    }
+
+    void didProcessAllPendingMouseEvents() override
+    {
+        m_mouseCallbacks.sendSuccess();
+    }
+
+    void addMouseCallback(Ref<MouseCallback>&& callback)
+    {
+        m_mouseCallbacks.append(WTFMove(callback));
+    }
+
+    void addKeyboardCallback(Ref<KeyboardCallback>&& callback)
+    {
+        m_keyboardCallbacks.append(WTFMove(callback));
+    }
+
+private:
+    CallbackList<KeyboardCallback> m_keyboardCallbacks;
+    CallbackList<MouseCallback> m_mouseCallbacks;
+};
+
+WebPageInspectorInputAgent::WebPageInspectorInputAgent(Inspector::BackendDispatcher& backendDispatcher, WebPageProxy& page)
+    : InspectorAgentBase("Input"_s)
+    , m_backendDispatcher(InputBackendDispatcher::create(backendDispatcher, this))
+    , m_page(page)
+    , m_inputObserver(makeUnique<InspectorInputObserver>())
+{
+    m_page.setObserber(m_inputObserver.get());
+}
+
+WebPageInspectorInputAgent::~WebPageInspectorInputAgent()
+{
+    m_page.setObserber(nullptr);
+}
+
+void WebPageInspectorInputAgent::didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*)
+{
+}
+
+void WebPageInspectorInputAgent::willDestroyFrontendAndBackend(Inspector::DisconnectReason)
+{
+}
+
+void WebPageInspectorInputAgent::dispatchKeyEvent(const String& in_type, const int* opt_in_modifiers, const String* opt_in_text, const String* opt_in_unmodifiedText, const String* opt_in_code, const String* opt_in_key, const int* opt_in_windowsVirtualKeyCode, const int* opt_in_nativeVirtualKeyCode, const bool* opt_in_autoRepeat, const bool* opt_in_isKeypad, const bool* opt_in_isSystemKey, const JSON::Array* opt_in_mac_commands, Ref<Inspector::InputBackendDispatcherHandler::DispatchKeyEventCallback>&& callback)
+{
+    WebKit::WebEvent::Type type;
+    if (in_type == "keyDown") {
+        type = WebKit::WebEvent::KeyDown;
+    } else if (in_type == "keyUp") {
+        type = WebKit::WebEvent::KeyUp;
+    } else {
+        callback->sendFailure("Unsupported event type.");
+        return;
+    }
+    OptionSet<WebEvent::Modifier> modifiers;
+    if (opt_in_modifiers)
+        modifiers = modifiers.fromRaw(*opt_in_modifiers);
+    String text;
+    if (opt_in_text)
+        text = *opt_in_text;
+    String unmodifiedText;
+    if (opt_in_unmodifiedText)
+        unmodifiedText = *opt_in_unmodifiedText;
+    String code;
+    if (opt_in_code)
+        code = *opt_in_code;
+    String key;
+    if (opt_in_key)
+        key = *opt_in_key;
+    int windowsVirtualKeyCode = 0;
+    if (opt_in_windowsVirtualKeyCode)
+        windowsVirtualKeyCode = *opt_in_windowsVirtualKeyCode;
+    int nativeVirtualKeyCode = 0;
+    if (opt_in_nativeVirtualKeyCode)
+        nativeVirtualKeyCode = *opt_in_nativeVirtualKeyCode;
+    Vector<String> commands;
+    if (opt_in_mac_commands) {
+      for (const auto& value : *opt_in_mac_commands) {
+        String command;
+        if (!value->asString(command)) {
+          callback->sendFailure("Command must be string");
+          return;
+        }
+        commands.append(command);
+      }
+    }
+
+    bool isAutoRepeat = false;
+    if (opt_in_autoRepeat)
+        isAutoRepeat = *opt_in_autoRepeat;
+    bool isKeypad = false;
+    if (opt_in_isKeypad)
+        isKeypad = *opt_in_isKeypad;
+    bool isSystemKey = false;
+    if (opt_in_isSystemKey)
+        isSystemKey = *opt_in_isSystemKey;
+    WallTime timestamp = WallTime::now();
+
+    m_inputObserver->addKeyboardCallback(WTFMove(callback));
+    platformDispatchKeyEvent(
+        type,
+        text,
+        unmodifiedText,
+        key,
+        code,
+        windowsVirtualKeyCode,
+        nativeVirtualKeyCode,
+        isAutoRepeat,
+        isKeypad,
+        isSystemKey,
+        modifiers,
+        commands,
+        timestamp);
+}
+
+void WebPageInspectorInputAgent::dispatchMouseEvent(const String& in_type, int in_x, int in_y, const int* opt_in_modifiers, const String* opt_in_button, const int* opt_in_buttons, const int* opt_in_clickCount, const int* opt_in_deltaX, const int* opt_in_deltaY, Ref<DispatchMouseEventCallback>&& callback)
+{
+    WebEvent::Type type = WebEvent::NoType;
+    if (in_type == "down")
+        type = WebEvent::MouseDown;
+    else if (in_type == "up")
+        type = WebEvent::MouseUp;
+    else if (in_type == "move")
+        type = WebEvent::MouseMove;
+    else {
+        callback->sendFailure("Unsupported event type");
+        return;
+    }
+
+    OptionSet<WebEvent::Modifier> modifiers;
+    if (opt_in_modifiers)
+        modifiers = modifiers.fromRaw(*opt_in_modifiers);
+
+    WebMouseEvent::Button button = WebMouseEvent::NoButton;
+    if (opt_in_button) {
+        if (*opt_in_button == "left")
+            button = WebMouseEvent::LeftButton;
+        else if (*opt_in_button == "middle")
+            button = WebMouseEvent::MiddleButton;
+        else if (*opt_in_button == "right")
+            button = WebMouseEvent::RightButton;
+        else if (*opt_in_button == "none")
+            button = WebMouseEvent::NoButton;
+        else {
+            callback->sendFailure("Unsupported button");
+            return;
+        }
+    }
+
+    unsigned short buttons = 0;
+    if (opt_in_buttons)
+        buttons = *opt_in_buttons;
+
+    int clickCount = 0;
+    if (opt_in_clickCount)
+        clickCount = *opt_in_clickCount;
+    int deltaX = 0;
+    if (opt_in_deltaX)
+        deltaX = *opt_in_deltaX;
+    int deltaY = 0;
+    if (opt_in_deltaY)
+        deltaY = *opt_in_deltaY;
+    m_inputObserver->addMouseCallback(WTFMove(callback));
+#if PLATFORM(WPE)
+    platformDispatchMouseEvent(type, in_x, in_y, button, modifiers);
+#elif PLATFORM(MAC)
+    platformDispatchMouseEvent(in_type, in_x, in_y, opt_in_modifiers, opt_in_button, opt_in_clickCount);
+#elif PLATFORM(GTK)
+    WallTime timestamp = WallTime::now();
+    NativeWebMouseEvent event(
+        type,
+        button,
+        buttons,
+        {in_x, in_y},
+        WebCore::IntPoint(),
+        deltaX,
+        deltaY,
+        0,
+        clickCount,
+        modifiers,
+        timestamp);
+    m_page.handleMouseEvent(event);
+#endif
+}
+
+void WebPageInspectorInputAgent::goBack(Inspector::ErrorString&)
+{
+    auto navigation = m_page.goBack();
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorInputAgent.h b/Source/WebKit/UIProcess/WebPageInspectorInputAgent.h
new file mode 100644
index 00000000000..b2f4827eede
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorInputAgent.h
@@ -0,0 +1,57 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "WebEvent.h"
+
+#include <JavaScriptCore/InspectorAgentBase.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class BackendDispatcher;
+class FrontendChannel;
+class FrontendRouter;
+}
+
+namespace WebKit {
+
+class NativeWebKeyboardEvent;
+class WebPageProxy;
+
+class WebPageInspectorInputAgent : public Inspector::InspectorAgentBase, public Inspector::InputBackendDispatcherHandler {
+    WTF_MAKE_NONCOPYABLE(WebPageInspectorInputAgent);
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    WebPageInspectorInputAgent(Inspector::BackendDispatcher& backendDispatcher, WebPageProxy& page);
+    ~WebPageInspectorInputAgent() override;
+
+    void didCreateFrontendAndBackend(Inspector::FrontendRouter*, Inspector::BackendDispatcher*) override;
+    void willDestroyFrontendAndBackend(Inspector::DisconnectReason) override;
+
+    void dispatchKeyEvent(const String& in_type, const int* opt_in_modifiers, const String* opt_in_text, const String* opt_in_unmodifiedText, const String* opt_in_code, const String* opt_in_key, const int* opt_in_windowsVirtualKeyCode, const int* opt_in_nativeVirtualKeyCode, const bool* opt_in_autoRepeat, const bool* opt_in_isKeypad, const bool* opt_in_isSystemKey, const JSON::Array*, Ref<DispatchKeyEventCallback>&& callback) override;
+    void dispatchMouseEvent(const String& in_type, int in_x, int in_y, const int* opt_in_modifiers, const String* opt_in_button, const int* opt_in_buttons, const int* opt_in_clickCount, const int* opt_in_deltaX, const int* opt_in_deltaY, Ref<DispatchMouseEventCallback>&& callback) override;
+    void goBack(Inspector::ErrorString&) override;
+
+private:
+    void platformDispatchKeyEvent(WebKeyboardEvent::Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<WebEvent::Modifier> modifiers, Vector<String>& commands, WallTime timestamp);
+#if PLATFORM(WPE)
+    void platformDispatchMouseEvent(WebMouseEvent::Type type, int x, int y, WebMouseEvent::Button button, OptionSet<WebEvent::Modifier> modifiers);
+#endif
+#if PLATFORM(MAC)
+    void platformDispatchMouseEvent(const String& type, int x, int y, const int* modifier, const String* button, const int* clickCount);
+#endif
+
+    Ref<Inspector::InputBackendDispatcher> m_backendDispatcher;
+    WebPageProxy& m_page;
+    // Keep track of currently active modifiers across multiple keystrokes.
+    // Most platforms do not track current modifiers from synthesized events.
+    unsigned m_currentModifiers { 0 };
+    class InspectorInputObserver;
+    std::unique_ptr<InspectorInputObserver> m_inputObserver;
+};
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.cpp b/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.cpp
new file mode 100644
index 00000000000..7b52be400be
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.cpp
@@ -0,0 +1,109 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorTargetProxy.h"
+
+#include "InspectorDialogAgent.h"
+#include "ProvisionalPageProxy.h"
+#include "WebPageInspectorController.h"
+#include "WebPageInspectorEmulationAgent.h"
+#include "WebPageInspectorInputAgent.h"
+#include "WebPageMessages.h"
+#include "WebPageProxy.h"
+#include "WebProcessProxy.h"
+#include <JavaScriptCore/InspectorBackendDispatcher.h>
+#include <JavaScriptCore/InspectorBackendDispatchers.h>
+#include <JavaScriptCore/InspectorFrontendRouter.h>
+#include <JavaScriptCore/InspectorTargetAgent.h>
+
+namespace WebKit {
+
+using namespace Inspector;
+
+namespace {
+
+class TargetFrontendChannel final : public FrontendChannel {
+    WTF_MAKE_NONCOPYABLE(TargetFrontendChannel);
+public:
+    TargetFrontendChannel(InspectorTargetAgent& targetAgent, const String& targetId, FrontendChannel::ConnectionType type)
+        : m_targetAgent(targetAgent)
+        , m_targetId(targetId)
+        , m_connectionType(type)
+    {
+    }
+    ~TargetFrontendChannel() override = default;
+
+    ConnectionType connectionType() const override { return m_connectionType; }
+    void sendMessageToFrontend(const String& message) override
+    {
+        m_targetAgent.sendMessageFromTargetToFrontend(m_targetId, message);
+    }
+
+private:
+    InspectorTargetAgent& m_targetAgent;
+    String m_targetId;
+    FrontendChannel::ConnectionType m_connectionType;
+};
+
+} // namespace
+
+std::unique_ptr<WebPageInspectorTargetProxy> WebPageInspectorTargetProxy::create(WebPageProxy& page, Inspector::InspectorTargetAgent& targetAgent, const String& targetId)
+{
+    return makeUnique<WebPageInspectorTargetProxy>(page, nullptr, targetAgent, targetId);
+}
+
+std::unique_ptr<WebPageInspectorTargetProxy> WebPageInspectorTargetProxy::create(ProvisionalPageProxy& provisionalPage, Inspector::InspectorTargetAgent& targetAgent, const String& targetId)
+{
+    return makeUnique<WebPageInspectorTargetProxy>(provisionalPage.page(), &provisionalPage, targetAgent, targetId);
+}
+
+WebPageInspectorTargetProxy::WebPageInspectorTargetProxy(WebPageProxy& page, ProvisionalPageProxy* provisionalPage, Inspector::InspectorTargetAgent& targetAgent, const String& targetId)
+    : InspectorTargetProxy(page, provisionalPage, targetId, Inspector::InspectorTargetType::Page)
+    , m_frontendRouter(FrontendRouter::create())
+    , m_backendDispatcher(BackendDispatcher::create(m_frontendRouter.copyRef()))
+    , m_targetAgent(targetAgent)
+{
+    m_agents.append(std::make_unique<WebPageInspectorEmulationAgent>(m_backendDispatcher.get(), page));
+    m_agents.append(std::make_unique<WebPageInspectorInputAgent>(m_backendDispatcher.get(), page));
+    m_agents.append(std::make_unique<InspectorDialogAgent>(m_backendDispatcher.get(), m_frontendRouter.get(), page));
+}
+
+void WebPageInspectorTargetProxy::connect(Inspector::FrontendChannel::ConnectionType connectionType)
+{
+    InspectorTargetProxy::connect(connectionType);
+    ASSERT(!m_frontendChannel);
+    if (m_frontendChannel)
+        return;
+    m_frontendChannel = std::make_unique<TargetFrontendChannel>(m_targetAgent, identifier(), connectionType);
+    m_frontendRouter->connectFrontend(*m_frontendChannel);
+}
+
+void WebPageInspectorTargetProxy::disconnect()
+{
+    ASSERT(m_frontendChannel);
+    m_frontendRouter->disconnectAllFrontends();
+    m_frontendChannel.reset();
+    InspectorTargetProxy::disconnect();
+}
+
+void WebPageInspectorTargetProxy::sendMessageToTargetBackend(const String& message)
+{
+    if (m_backendDispatcher->dispatch(message, BackendDispatcher::Mode::ContinueIfDomainIsMissing) == BackendDispatcher::DispatchResult::Finished)
+        return;
+    if (m_page.inspectorController().dispatchMessageToTargetBackend(message))
+        return;
+    InspectorTargetProxy::sendMessageToTargetBackend(message);
+}
+
+void WebPageInspectorTargetProxy::activate(String& error)
+{
+    platformActivate(error);
+}
+
+void WebPageInspectorTargetProxy::close(String& error)
+{
+    m_page.closePage();
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.h b/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.h
new file mode 100644
index 00000000000..0655b5ea376
--- /dev/null
+++ b/Source/WebKit/UIProcess/WebPageInspectorTargetProxy.h
@@ -0,0 +1,45 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "InspectorTargetProxy.h"
+#include <JavaScriptCore/InspectorAgentRegistry.h>
+#include <wtf/Forward.h>
+#include <wtf/Noncopyable.h>
+
+namespace Inspector {
+class BackendDispatcher;
+class InspectorTargetAgent;
+}
+
+namespace WebKit {
+
+class WebPageProxy;
+
+class WebPageInspectorTargetProxy final : public InspectorTargetProxy {
+    WTF_MAKE_FAST_ALLOCATED;
+    WTF_MAKE_NONCOPYABLE(WebPageInspectorTargetProxy);
+public:
+    static std::unique_ptr<WebPageInspectorTargetProxy> create(WebPageProxy&, Inspector::InspectorTargetAgent&, const String& targetId);
+    static std::unique_ptr<WebPageInspectorTargetProxy> create(ProvisionalPageProxy&, Inspector::InspectorTargetAgent&, const String& targetId);
+    WebPageInspectorTargetProxy(WebPageProxy&, ProvisionalPageProxy*, Inspector::InspectorTargetAgent&, const String& targetId);
+    ~WebPageInspectorTargetProxy() = default;
+
+    void connect(Inspector::FrontendChannel::ConnectionType) override;
+    void disconnect() override;
+    void sendMessageToTargetBackend(const String&) override;
+    void activate(String& error) override;
+    void close(String& error) override;
+
+private:
+    void platformActivate(String& error) const;
+
+    Ref<Inspector::FrontendRouter> m_frontendRouter;
+    Ref<Inspector::BackendDispatcher> m_backendDispatcher;
+    Inspector::InspectorTargetAgent& m_targetAgent;
+    Inspector::AgentRegistry m_agents;
+    std::unique_ptr<Inspector::FrontendChannel> m_frontendChannel;
+};
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/WebPageProxy.cpp b/Source/WebKit/UIProcess/WebPageProxy.cpp
index e3b45239979..3f77f920dfa 100644
--- a/Source/WebKit/UIProcess/WebPageProxy.cpp
+++ b/Source/WebKit/UIProcess/WebPageProxy.cpp
@@ -885,6 +885,7 @@ void WebPageProxy::finishAttachingToWebProcess(ProcessLaunchReason reason)
     m_pageLoadState.didSwapWebProcesses();
     if (reason != ProcessLaunchReason::InitialProcess)
         m_drawingArea->waitForBackingStoreUpdateOnNextPaint();
+    m_inspectorController->didFinishAttachingToWebProcess();
 }
 
 void WebPageProxy::didAttachToRunningProcess()
@@ -1656,6 +1657,11 @@ void WebPageProxy::setControlledByAutomation(bool controlled)
     m_process->processPool().sendToNetworkingProcess(Messages::NetworkProcess::SetSessionIsControlledByAutomation(m_websiteDataStore->sessionID(), m_controlledByAutomation));
 }
 
+void WebPageProxy::setObserber(InputProcessingObserver* observer)
+{
+    m_inputProcessingObserver = observer;
+}
+
 void WebPageProxy::createInspectorTarget(const String& targetId, Inspector::InspectorTargetType type)
 {
     m_inspectorController->createInspectorTarget(targetId, type);
@@ -5400,6 +5406,8 @@ void WebPageProxy::runJavaScriptAlert(FrameIdentifier frameID, SecurityOriginDat
         if (auto* automationSession = process().processPool().automationSession())
             automationSession->willShowJavaScriptDialog(*this);
     }
+    if (m_inspectorDialogAgent)
+        m_inspectorDialogAgent->javascriptDialogOpening("alert"_s, message);
     m_uiClient->runJavaScriptAlert(*this, message, frame, WTFMove(securityOrigin), WTFMove(reply));
 }
 
@@ -5419,6 +5427,8 @@ void WebPageProxy::runJavaScriptConfirm(FrameIdentifier frameID, SecurityOriginD
         if (auto* automationSession = process().processPool().automationSession())
             automationSession->willShowJavaScriptDialog(*this);
     }
+    if (m_inspectorDialogAgent)
+        m_inspectorDialogAgent->javascriptDialogOpening("confirm"_s, message);
 
     m_uiClient->runJavaScriptConfirm(*this, message, frame, WTFMove(securityOrigin), WTFMove(reply));
 }
@@ -5438,6 +5448,8 @@ void WebPageProxy::runJavaScriptPrompt(FrameIdentifier frameID, SecurityOriginDa
         if (auto* automationSession = process().processPool().automationSession())
             automationSession->willShowJavaScriptDialog(*this);
     }
+    if (m_inspectorDialogAgent)
+        m_inspectorDialogAgent->javascriptDialogOpening("prompt"_s, message, &defaultValue);
 
     m_uiClient->runJavaScriptPrompt(*this, message, defaultValue, frame, WTFMove(securityOrigin), WTFMove(reply));
 }
@@ -5597,6 +5609,8 @@ void WebPageProxy::runBeforeUnloadConfirmPanel(FrameIdentifier frameID, Security
             return;
         }
     }
+    if (m_inspectorDialogAgent)
+        m_inspectorDialogAgent->javascriptDialogOpening("beforeunload"_s, message);
 
     // Since runBeforeUnloadConfirmPanel() can spin a nested run loop we need to turn off the responsiveness timer.
     m_process->responsivenessTimer().stop();
@@ -6617,6 +6631,8 @@ void WebPageProxy::didReceiveEvent(uint32_t opaqueType, bool handled)
             if (auto* automationSession = process().processPool().automationSession())
                 automationSession->mouseEventsFlushedForPage(*this);
             pageClient().didFinishProcessingAllPendingMouseEvents();
+            if (m_inputProcessingObserver)
+                m_inputProcessingObserver->didProcessAllPendingMouseEvents();
         }
 
         break;
@@ -6643,7 +6659,6 @@ void WebPageProxy::didReceiveEvent(uint32_t opaqueType, bool handled)
     case WebEvent::RawKeyDown:
     case WebEvent::Char: {
         LOG(KeyHandling, "WebPageProxy::didReceiveEvent: %s (queue empty %d)", webKeyboardEventTypeString(type), m_keyEventQueue.isEmpty());
-
         MESSAGE_CHECK(m_process, !m_keyEventQueue.isEmpty());
         NativeWebKeyboardEvent event = m_keyEventQueue.takeFirst();
 
@@ -6663,7 +6678,6 @@ void WebPageProxy::didReceiveEvent(uint32_t opaqueType, bool handled)
         // The call to doneWithKeyEvent may close this WebPage.
         // Protect against this being destroyed.
         Ref<WebPageProxy> protect(*this);
-
         pageClient().doneWithKeyEvent(event, handled);
         if (!handled)
             m_uiClient->didNotHandleKeyEvent(this, event);
@@ -6672,6 +6686,8 @@ void WebPageProxy::didReceiveEvent(uint32_t opaqueType, bool handled)
         if (!canProcessMoreKeyEvents) {
             if (auto* automationSession = process().processPool().automationSession())
                 automationSession->keyboardEventsFlushedForPage(*this);
+            if (m_inputProcessingObserver)
+                m_inputProcessingObserver->didProcessAllPendingKeyboardEvents();
         }
         break;
     }
diff --git a/Source/WebKit/UIProcess/WebPageProxy.h b/Source/WebKit/UIProcess/WebPageProxy.h
index ae3852221d4..6ad08957deb 100644
--- a/Source/WebKit/UIProcess/WebPageProxy.h
+++ b/Source/WebKit/UIProcess/WebPageProxy.h
@@ -35,6 +35,7 @@
 #include "FocusedElementInformation.h"
 #include "GeolocationPermissionRequestManagerProxy.h"
 #include "HiddenPageThrottlingAutoIncreasesCounter.h"
+#include "InspectorDialogAgent.h"
 #include "LayerTreeContext.h"
 #include "MessageSender.h"
 #include "NotificationPermissionRequestManagerProxy.h"
@@ -471,6 +472,8 @@ public:
     void setControlledByAutomation(bool);
 
     WebPageInspectorController& inspectorController() { return *m_inspectorController; }
+    InspectorDialogAgent* inspectorDialogAgent() { return m_inspectorDialogAgent; }
+    void setInspectorDialogAgent(InspectorDialogAgent * dialogAgent) { m_inspectorDialogAgent = dialogAgent; }
 
 #if PLATFORM(IOS_FAMILY)
     void showInspectorIndication();
@@ -536,6 +539,14 @@ public:
 
     void setPageLoadStateObserver(std::unique_ptr<PageLoadState::Observer>&&);
 
+    class InputProcessingObserver {
+    public:
+        virtual ~InputProcessingObserver() = default;
+        virtual void didProcessAllPendingKeyboardEvents() = 0;
+        virtual void didProcessAllPendingMouseEvents() = 0;
+    };
+    void setObserber(InputProcessingObserver*);
+
     void initializeWebPage();
     void setDrawingArea(std::unique_ptr<DrawingAreaProxy>&&);
 
@@ -2243,6 +2254,7 @@ private:
     bool m_treatsSHA1CertificatesAsInsecure { true };
 
     RefPtr<WebInspectorProxy> m_inspector;
+    InspectorDialogAgent* m_inspectorDialogAgent { nullptr };
 
 #if ENABLE(FULLSCREEN_API)
     std::unique_ptr<WebFullScreenManagerProxy> m_fullScreenManager;
@@ -2594,6 +2606,7 @@ private:
 #if ENABLE(REMOTE_INSPECTOR)
     std::unique_ptr<WebPageDebuggable> m_inspectorDebuggable;
 #endif
+    InputProcessingObserver* m_inputProcessingObserver { nullptr };
 
     Optional<SpellDocumentTag> m_spellDocumentTag;
 
diff --git a/Source/WebKit/UIProcess/WebProcessPool.h b/Source/WebKit/UIProcess/WebProcessPool.h
index abe32f20524..3dc3c767103 100644
--- a/Source/WebKit/UIProcess/WebProcessPool.h
+++ b/Source/WebKit/UIProcess/WebProcessPool.h
@@ -414,7 +414,7 @@ public:
 
     void windowServerConnectionStateChanged();
 
-#if USE(SOUP)
+#if USE(SOUP) || PLATFORM(COCOA)
     void setIgnoreTLSErrors(bool);
     bool ignoreTLSErrors() const { return m_ignoreTLSErrors; }
 #endif
@@ -709,7 +709,7 @@ private:
     HashMap<uint64_t, RefPtr<DictionaryCallback>> m_dictionaryCallbacks;
     HashMap<uint64_t, RefPtr<StatisticsRequest>> m_statisticsRequests;
 
-#if USE(SOUP)
+#if USE(SOUP) || PLATFORM(COCOA)
     bool m_ignoreTLSErrors { true };
 #endif
 
diff --git a/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.cpp b/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.cpp
new file mode 100644
index 00000000000..e632fe864cb
--- /dev/null
+++ b/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.cpp
@@ -0,0 +1,103 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "InspectorBrowserAgentClientGLib.h"
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "InspectorBrowserAgent.h"
+#include "WebKitBrowserInspectorPrivate.h"
+#include "WebKitWebContextPrivate.h"
+#include "WebKitWebsiteDataManagerPrivate.h"
+#include "WebKitWebViewPrivate.h"
+#include "WebPageProxy.h"
+#include <wtf/HashMap.h>
+#include <wtf/RefPtr.h>
+#include <wtf/text/StringView.h>
+#include <wtf/text/WTFString.h>
+
+namespace WebKit {
+
+static Vector<WebPageProxy*> collectPages(Optional<PAL::SessionID> sessionID)
+{
+    Vector<WebPageProxy*> result;
+    for (WebProcessPool* pool : WebProcessPool::allProcessPools()) {
+        for (auto& process : pool->processes()) {
+            for (auto* page : process->pages()) {
+                if (!sessionID || page->sessionID() == sessionID)
+                    result.append(page);
+            }
+        }
+    }
+    return result;
+}
+
+static void closeAllPages(Optional<PAL::SessionID> sessionID)
+{
+    Vector<WebPageProxy*> pages = collectPages(sessionID);
+    for (auto* page : pages)
+        page->closePage();
+}
+
+InspectorBrowserAgentClientGlib::InspectorBrowserAgentClientGlib()
+{
+}
+
+RefPtr<WebPageProxy> InspectorBrowserAgentClientGlib::createPage(WTF::String& error, PAL::SessionID sessionID)
+{
+    WebKitWebContext* context;
+    if (!sessionID || webkitWebContextGetProcessPool(webkit_web_context_get_default()).websiteDataStore()->sessionID() == sessionID)
+      context = webkit_web_context_get_default();
+    else
+      context = m_idToContext.get(sessionID);
+
+    if (context == nullptr) {
+        error = "Context with provided id not found";
+        return nullptr;
+    }
+
+    RefPtr<WebPageProxy> page = webkitBrowserInspectorCreateNewPageInContext(context);
+    if (page == nullptr)
+        error = "Failed to create new page in the context";
+    return page;
+}
+
+void InspectorBrowserAgentClientGlib::closeAllWindows()
+{
+    closeAllPages(Optional<PAL::SessionID>());
+    m_idToContext.clear();
+    // FIXME(yurys): call g_main_loop_quit() ?
+}
+
+static PAL::SessionID sessionIDFromContext(WebKitWebContext* context)
+{
+    WebKitWebsiteDataManager* data_manager = webkit_web_context_get_website_data_manager(context);
+    WebsiteDataStore& websiteDataStore = webkitWebsiteDataManagerGetDataStore(data_manager);
+    return websiteDataStore.sessionID();
+}
+
+BrowserContext InspectorBrowserAgentClientGlib::createBrowserContext(WTF::String& error)
+{
+    BrowserContext browserContext;
+    GRefPtr<WebKitWebsiteDataManager> data_manager = adoptGRef(webkit_website_data_manager_new_ephemeral());
+    GRefPtr<WebKitWebContext> context = adoptGRef(WEBKIT_WEB_CONTEXT(g_object_new(WEBKIT_TYPE_WEB_CONTEXT, "website-data-manager", data_manager.get(), "process-swap-on-cross-site-navigation-enabled", true, nullptr)));
+    if (!context) {
+        error = "Failed to create GLib ephemeral context";
+        return browserContext;
+    }
+    browserContext.processPool = &webkitWebContextGetProcessPool(context.get());
+    browserContext.dataStore = &webkitWebsiteDataManagerGetDataStore(data_manager.get());
+    PAL::SessionID sessionID = sessionIDFromContext(context.get());
+    m_idToContext.set(sessionID, WTFMove(context));
+    return browserContext;
+}
+
+void InspectorBrowserAgentClientGlib::deleteBrowserContext(WTF::String& error, PAL::SessionID sessionID)
+{
+    m_idToContext.remove(sessionID);
+}
+
+} // namespace WebKit
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.h b/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.h
new file mode 100644
index 00000000000..37a5e7ad390
--- /dev/null
+++ b/Source/WebKit/UIProcess/glib/InspectorBrowserAgentClientGLib.h
@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#if ENABLE(REMOTE_INSPECTOR)
+
+#include "InspectorBrowserAgentClient.h"
+#include "WebKitWebContext.h"
+#include <wtf/Forward.h>
+#include <wtf/HashMap.h>
+#include <wtf/glib/GRefPtr.h>
+#include <wtf/text/StringHash.h>
+
+namespace WebKit {
+
+class InspectorBrowserAgentClientGlib : public InspectorBrowserAgentClient {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    InspectorBrowserAgentClientGlib();
+    ~InspectorBrowserAgentClientGlib() override = default;
+
+    RefPtr<WebPageProxy> createPage(WTF::String& error, PAL::SessionID) override;
+    void closeAllWindows() override;
+    BrowserContext createBrowserContext(WTF::String& error) override;
+    void deleteBrowserContext(WTF::String& error, PAL::SessionID) override;
+
+private:
+    WebKitWebContext* findContext(WTF::String& error, PAL::SessionID);
+
+    HashMap<PAL::SessionID, GRefPtr<WebKitWebContext>> m_idToContext;
+};
+
+} // namespace API
+
+#endif // ENABLE(REMOTE_INSPECTOR)
diff --git a/Source/WebKit/UIProcess/gtk/WebPageInspectorEmulationAgentGtk.cpp b/Source/WebKit/UIProcess/gtk/WebPageInspectorEmulationAgentGtk.cpp
new file mode 100644
index 00000000000..e38a4ad3e2f
--- /dev/null
+++ b/Source/WebKit/UIProcess/gtk/WebPageInspectorEmulationAgentGtk.cpp
@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "DrawingAreaProxyCoordinatedGraphics.h"
+#include "WebPageInspectorEmulationAgent.h"
+#include "WebPageProxy.h"
+#include <WebCore/IntSize.h>
+#include <gtk/gtk.h>
+
+namespace WebKit {
+void WebPageInspectorEmulationAgent::platformSetSize(int width, int height, Function<void (const String& error)>&& callback)
+{
+    GtkWidget* viewWidget = m_page.viewWidget();
+    GtkWidget* window = gtk_widget_get_toplevel(viewWidget);
+    if (!window) {
+        callback("Cannot find parent window"_s);
+        return;
+    }
+    if (!GTK_IS_WINDOW(window)) {
+        callback("Toplevel is not a window"_s);
+        return;
+    }
+    GtkAllocation viewAllocation;
+    gtk_widget_get_allocation(viewWidget, &viewAllocation);
+
+    GtkAllocation windowAllocation;
+    gtk_widget_get_allocation(window, &windowAllocation);
+
+    width += windowAllocation.width - viewAllocation.width;
+    height += windowAllocation.height - viewAllocation.height;
+
+    if (auto* drawingArea = static_cast<DrawingAreaProxyCoordinatedGraphics*>(m_page.drawingArea())) {
+        drawingArea->waitForBackingStoreUpdate([callback = WTFMove(callback)]() {
+            callback(String());
+        });
+    } else {
+        callback("No backing store for window"_s);
+    }
+    gtk_window_resize(GTK_WINDOW(window), width, height);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/gtk/WebPageInspectorInputAgentGtk.cpp b/Source/WebKit/UIProcess/gtk/WebPageInspectorInputAgentGtk.cpp
new file mode 100644
index 00000000000..e9af79dad57
--- /dev/null
+++ b/Source/WebKit/UIProcess/gtk/WebPageInspectorInputAgentGtk.cpp
@@ -0,0 +1,85 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorInputAgent.h"
+
+#include "KeyBindingTranslator.h"
+#include "NativeWebKeyboardEvent.h"
+#include "WebPageProxy.h"
+#include <WebCore/PlatformKeyboardEvent.h>
+
+namespace WebKit {
+
+static Vector<String> commandsForKeyEvent(GdkEventType type, unsigned keyVal, unsigned state)
+{
+    ASSERT(type == GDK_KEY_PRESS || type == GDK_KEY_RELEASE);
+
+    GUniquePtr<GdkEvent> event(gdk_event_new(type));
+    event->key.keyval = keyVal;
+    event->key.time = GDK_CURRENT_TIME;
+    event->key.state = state;
+    // When synthesizing an event, an invalid hardware_keycode value can cause it to be badly processed by GTK+.
+    GUniqueOutPtr<GdkKeymapKey> keys;
+    int keysCount;
+    if (gdk_keymap_get_entries_for_keyval(gdk_keymap_get_default(), keyVal, &keys.outPtr(), &keysCount) && keysCount)
+        event->key.hardware_keycode = keys.get()[0].keycode;
+    return KeyBindingTranslator().commandsForKeyEvent(&event->key);
+}
+
+static unsigned modifiersToEventState(OptionSet<WebEvent::Modifier> modifiers)
+{
+    unsigned state = 0;
+    if (modifiers.contains(WebEvent::Modifier::ControlKey))
+        state |= GDK_CONTROL_MASK;
+    if (modifiers.contains(WebEvent::Modifier::ShiftKey))
+        state |= GDK_SHIFT_MASK;
+    if (modifiers.contains(WebEvent::Modifier::AltKey))
+        state |= GDK_META_MASK;
+    if (modifiers.contains(WebEvent::Modifier::CapsLockKey))
+        state |= GDK_LOCK_MASK;
+    return state;
+}
+
+void WebPageInspectorInputAgent::platformDispatchKeyEvent(WebKeyboardEvent::Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<WebEvent::Modifier> modifiers, Vector<String>& macCommands, WallTime timestamp)
+{
+    Vector<String> commands;
+    const guint keyVal = WebCore::PlatformKeyboardEvent::gdkKeyCodeForWindowsKeyCode(windowsVirtualKeyCode);
+    String keyIdentifier;
+    if (keyVal) {
+        GdkEventType event = GDK_NOTHING;
+        switch (type)
+        {
+        case WebKeyboardEvent::KeyDown:
+            event = GDK_KEY_PRESS;
+            break;
+        case WebKeyboardEvent::KeyUp:
+            event = GDK_KEY_RELEASE;
+            break;
+        default:
+            fprintf(stderr, "Unsupported event type = %d\n", type);
+            break;
+        }
+        unsigned state = modifiersToEventState(modifiers);
+        commands = commandsForKeyEvent(event, keyVal, state);
+        keyIdentifier = WebCore::PlatformKeyboardEvent::keyIdentifierForGdkKeyCode(keyVal);
+    }
+    NativeWebKeyboardEvent event(
+        type,
+        text,
+        unmodifiedText,
+        key,
+        code,
+        keyIdentifier,
+        windowsVirtualKeyCode,
+        nativeVirtualKeyCode,
+        isAutoRepeat,
+        isKeypad,
+        isSystemKey,
+        modifiers,
+        timestamp,
+        WTFMove(commands));
+    m_page.handleKeyboardEvent(event);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/gtk/WebPageInspectorTargetProxyGtk.cpp b/Source/WebKit/UIProcess/gtk/WebPageInspectorTargetProxyGtk.cpp
new file mode 100644
index 00000000000..5805ee6fdf4
--- /dev/null
+++ b/Source/WebKit/UIProcess/gtk/WebPageInspectorTargetProxyGtk.cpp
@@ -0,0 +1,22 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorTargetProxy.h"
+
+#include "WebPageProxy.h"
+#include <WebCore/GtkUtilities.h>
+#include <gtk/gtk.h>
+
+namespace WebKit {
+
+void WebPageInspectorTargetProxy::platformActivate(String& error) const
+{
+    GtkWidget* parent = gtk_widget_get_toplevel(m_page.viewWidget());
+    if (WebCore::widgetIsOnscreenToplevelWindow(parent))
+        gtk_window_present(GTK_WINDOW(parent));
+    else
+        error = "The view is not on screen";
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/ios/PageClientImplIOS.mm b/Source/WebKit/UIProcess/ios/PageClientImplIOS.mm
index 4df3ad55550..13c48f39925 100644
--- a/Source/WebKit/UIProcess/ios/PageClientImplIOS.mm
+++ b/Source/WebKit/UIProcess/ios/PageClientImplIOS.mm
@@ -409,6 +409,8 @@ IntRect PageClientImpl::rootViewToAccessibilityScreen(const IntRect& rect)
     
 void PageClientImpl::doneWithKeyEvent(const NativeWebKeyboardEvent& event, bool eventWasHandled)
 {
+    if (!event.nativeEvent())
+        return;
     [m_contentView _didHandleKeyEvent:event.nativeEvent() eventWasHandled:eventWasHandled];
 }
 
diff --git a/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.h b/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.h
new file mode 100644
index 00000000000..03aff71e9f9
--- /dev/null
+++ b/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.h
@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "InspectorBrowserAgentClient.h"
+#include <wtf/Forward.h>
+
+OBJC_PROTOCOL(_WKBrowserInspectorDelegate);
+
+namespace WebKit {
+
+class InspectorBrowserAgentClientMac : public InspectorBrowserAgentClient {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    InspectorBrowserAgentClientMac(_WKBrowserInspectorDelegate* delegate);
+    ~InspectorBrowserAgentClientMac() override = default;
+
+    RefPtr<WebPageProxy> createPage(WTF::String& error, PAL::SessionID) override;
+    void closeAllWindows() override;
+    BrowserContext createBrowserContext(WTF::String& error) override;
+    void deleteBrowserContext(WTF::String& error, PAL::SessionID) override;
+  private:
+
+    _WKBrowserInspectorDelegate* delegate_;
+};
+
+
+} // namespace API
diff --git a/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.mm b/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.mm
new file mode 100644
index 00000000000..e3062b3651f
--- /dev/null
+++ b/Source/WebKit/UIProcess/mac/InspectorBrowserAgentClientMac.mm
@@ -0,0 +1,54 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#import "config.h"
+#import "InspectorBrowserAgentClientMac.h"
+
+#import <wtf/RefPtr.h>
+#import <wtf/text/WTFString.h>
+#import "WebPageProxy.h"
+#import "WebProcessPool.h"
+#import "WebsiteDataStore.h"
+#import "_WKBrowserInspector.h"
+#import "WKProcessPoolInternal.h"
+#import "WKWebsiteDataStoreInternal.h"
+#import "WKWebView.h"
+#import "WKWebViewInternal.h"
+
+namespace WebKit {
+
+InspectorBrowserAgentClientMac::InspectorBrowserAgentClientMac(_WKBrowserInspectorDelegate* delegate)
+  : delegate_(delegate)
+{
+}
+
+RefPtr<WebPageProxy> InspectorBrowserAgentClientMac::createPage(WTF::String& error, PAL::SessionID sessionID)
+{
+    WKWebView *webView = [delegate_ createNewPage:sessionID.toUInt64()];
+    if (!webView) {
+        error = "Internal error: can't create page in given context"_s;
+        return nil;
+    }
+    return [webView _page];
+}
+
+void InspectorBrowserAgentClientMac::closeAllWindows()
+{
+    [delegate_ quit];
+}
+
+BrowserContext InspectorBrowserAgentClientMac::createBrowserContext(WTF::String& error)
+{
+    _WKBrowserContext* wkBrowserContext = [[delegate_ createBrowserContext] autorelease];
+    BrowserContext browserContext;
+    browserContext.processPool = &static_cast<WebProcessPool&>([[wkBrowserContext processPool] _apiObject]);
+    browserContext.dataStore = &static_cast<WebsiteDataStore&>([[wkBrowserContext dataStore] _apiObject]);
+    return browserContext;
+}
+
+void InspectorBrowserAgentClientMac::deleteBrowserContext(WTF::String& error, PAL::SessionID sessionID)
+{
+    [delegate_ deleteBrowserContext:sessionID.toUInt64()];
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/mac/PageClientImplMac.h b/Source/WebKit/UIProcess/mac/PageClientImplMac.h
index 8016b56c160..bf5422a3a63 100644
--- a/Source/WebKit/UIProcess/mac/PageClientImplMac.h
+++ b/Source/WebKit/UIProcess/mac/PageClientImplMac.h
@@ -53,6 +53,8 @@ class PageClientImpl final : public PageClientImplCocoa
 #endif
     {
 public:
+    static void setHeadless(bool headless);
+
     PageClientImpl(NSView *, WKWebView *);
     virtual ~PageClientImpl();
 
diff --git a/Source/WebKit/UIProcess/mac/PageClientImplMac.mm b/Source/WebKit/UIProcess/mac/PageClientImplMac.mm
index bf7dc132b1e..6e495df29b0 100644
--- a/Source/WebKit/UIProcess/mac/PageClientImplMac.mm
+++ b/Source/WebKit/UIProcess/mac/PageClientImplMac.mm
@@ -105,6 +105,13 @@ static NSString * const kAXLoadCompleteNotification = @"AXLoadComplete";
 namespace WebKit {
 using namespace WebCore;
 
+static bool _headless = false;
+
+// static
+void PageClientImpl::setHeadless(bool headless) {
+    _headless = true;
+}
+
 PageClientImpl::PageClientImpl(NSView* view, WKWebView *webView)
     : PageClientImplCocoa(webView)
     , m_view(view)
@@ -163,6 +170,9 @@ NSWindow *PageClientImpl::activeWindow() const
 
 bool PageClientImpl::isViewWindowActive()
 {
+    if (_headless)
+        return true;
+
     ASSERT(hasProcessPrivilege(ProcessPrivilege::CanCommunicateWithWindowServer));
     NSWindow *activeViewWindow = activeWindow();
     return activeViewWindow.isKeyWindow || [NSApp keyWindow] == activeViewWindow;
@@ -170,6 +180,9 @@ bool PageClientImpl::isViewWindowActive()
 
 bool PageClientImpl::isViewFocused()
 {
+    if (_headless)
+        return true;
+
     // FIXME: This is called from the WebPageProxy constructor before we have a WebViewImpl.
     // Once WebViewImpl and PageClient merge, this won't be a problem.
     if (!m_impl)
@@ -193,6 +206,9 @@ void PageClientImpl::makeFirstResponder()
     
 bool PageClientImpl::isViewVisible()
 {
+    if (_headless)
+        return true;
+
     NSView *activeView = this->activeView();
     NSWindow *activeViewWindow = activeWindow();
 
@@ -456,6 +472,8 @@ IntRect PageClientImpl::rootViewToAccessibilityScreen(const IntRect& rect)
 
 void PageClientImpl::doneWithKeyEvent(const NativeWebKeyboardEvent& event, bool eventWasHandled)
 {
+    if (!event.nativeEvent())
+        return;
     m_impl->doneWithKeyEvent(event.nativeEvent(), eventWasHandled);
 }
 
@@ -931,6 +949,9 @@ void PageClientImpl::didRestoreScrollPosition()
 
 bool PageClientImpl::windowIsFrontWindowUnderMouse(const NativeWebMouseEvent& event)
 {
+    // Simulated event.
+    if (!event.nativeEvent())
+        return false;
     return m_impl->windowIsFrontWindowUnderMouse(event.nativeEvent());
 }
 
diff --git a/Source/WebKit/UIProcess/mac/WebPageInspectorEmulationAgentMac.mm b/Source/WebKit/UIProcess/mac/WebPageInspectorEmulationAgentMac.mm
new file mode 100644
index 00000000000..71d742789cb
--- /dev/null
+++ b/Source/WebKit/UIProcess/mac/WebPageInspectorEmulationAgentMac.mm
@@ -0,0 +1,22 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#import "config.h"
+#import "WebPageInspectorEmulationAgent.h"
+
+#import "WebPageProxy.h"
+
+namespace WebKit {
+
+void WebPageInspectorEmulationAgent::platformSetSize(int width, int height, Function<void (const String& error)>&& callback)
+{
+    NSWindow* window = m_page.platformWindow();
+    NSRect windowRect = [window frame];
+    NSRect viewRect = window.contentLayoutRect;
+    windowRect.size.width += width - viewRect.size.width;
+    windowRect.size.height += height - viewRect.size.height;
+    [window setFrame:windowRect display:YES animate:NO];
+    callback(String());
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/mac/WebPageInspectorInputAgentMac.mm b/Source/WebKit/UIProcess/mac/WebPageInspectorInputAgentMac.mm
new file mode 100644
index 00000000000..08394ef65f3
--- /dev/null
+++ b/Source/WebKit/UIProcess/mac/WebPageInspectorInputAgentMac.mm
@@ -0,0 +1,91 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#import "config.h"
+#import "NativeWebMouseEvent.h"
+#import "WebPageInspectorInputAgent.h"
+#import "WebPageProxy.h"
+#import <WebCore/IntPoint.h>
+#import <WebCore/IntSize.h>
+#import "NativeWebKeyboardEvent.h"
+#import <wtf/HexNumber.h>
+
+namespace WebKit {
+
+using namespace WebCore;
+
+void WebPageInspectorInputAgent::platformDispatchMouseEvent(const String& type, int x, int y, const int* optionalModifiers, const String* button, const int* optionalClickCount) {
+    IntPoint locationInWindow(x, y);
+
+    NSEventModifierFlags modifiers = optionalModifiers ? *optionalModifiers : 0;
+    int clickCount = optionalClickCount ? *optionalClickCount : 0;
+
+    NSTimeInterval timestamp = [NSDate timeIntervalSinceReferenceDate];
+    NSWindow *window = m_page.platformWindow();
+    NSInteger windowNumber = window.windowNumber;
+
+    NSEventType downEventType = (NSEventType)0;
+    NSEventType dragEventType = (NSEventType)0;
+    NSEventType upEventType = (NSEventType)0;
+
+    if (!button || *button == "none") {
+        downEventType = NSEventTypeMouseMoved;
+        dragEventType = NSEventTypeMouseMoved;
+        upEventType = NSEventTypeMouseMoved;
+    } else if (*button == "left") {
+        downEventType = NSEventTypeLeftMouseDown;
+        dragEventType = NSEventTypeLeftMouseDragged;
+        upEventType = NSEventTypeLeftMouseUp;
+    } else if (*button == "middle") {
+        downEventType = NSEventTypeOtherMouseDown;
+        dragEventType = NSEventTypeLeftMouseDragged;
+        upEventType = NSEventTypeOtherMouseUp;
+    } else if (*button == "right") {
+        downEventType = NSEventTypeRightMouseDown;
+        upEventType = NSEventTypeRightMouseUp;
+    }
+
+    NSInteger eventNumber = 0;
+
+    NSEvent* event = nil;
+    if (type == "move") {
+        event = [NSEvent mouseEventWithType:dragEventType location:locationInWindow modifierFlags:modifiers timestamp:timestamp windowNumber:windowNumber context:nil eventNumber:eventNumber clickCount:clickCount pressure:0.0f];
+    } else if (type == "down") {
+        event = [NSEvent mouseEventWithType:downEventType location:locationInWindow modifierFlags:modifiers timestamp:timestamp windowNumber:windowNumber context:nil eventNumber:eventNumber clickCount:clickCount pressure:WebCore::ForceAtClick];
+    } else if (type == "up") {
+        event = [NSEvent mouseEventWithType:upEventType location:locationInWindow modifierFlags:modifiers timestamp:timestamp windowNumber:windowNumber context:nil eventNumber:eventNumber clickCount:clickCount pressure:0.0f];
+    }
+
+    if (event) {
+        NativeWebMouseEvent nativeEvent(event, nil, [window contentView]);
+        m_page.handleMouseEvent(nativeEvent);
+    }
+}
+
+void WebPageInspectorInputAgent::platformDispatchKeyEvent(WebKeyboardEvent::Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<WebEvent::Modifier> modifiers, Vector<String>& commands, WallTime timestamp)
+{
+    String keyIdentifier = key.length() == 1 ? makeString("U+", hex(toASCIIUpper(key.characterAt(0)), 4)) : key;
+    Vector<WebCore::KeypressCommand> macCommands;
+    for (const String& command : commands)
+      macCommands.append(WebCore::KeypressCommand(command.utf8().data()));
+    if (text.length() > 0 && macCommands.size() == 0)
+      macCommands.append(WebCore::KeypressCommand("insertText:", text));
+    NativeWebKeyboardEvent event(
+        type,
+        text,
+        unmodifiedText,
+        key,
+        code,
+        keyIdentifier,
+        windowsVirtualKeyCode,
+        nativeVirtualKeyCode,
+        isAutoRepeat,
+        isKeypad,
+        isSystemKey,
+        modifiers,
+        timestamp,
+        WTFMove(macCommands));
+    m_page.handleKeyboardEvent(event);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/mac/WebPageInspectorTargetProxyMac.mm b/Source/WebKit/UIProcess/mac/WebPageInspectorTargetProxyMac.mm
new file mode 100644
index 00000000000..2061f6d129b
--- /dev/null
+++ b/Source/WebKit/UIProcess/mac/WebPageInspectorTargetProxyMac.mm
@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#import "config.h"
+#import "WebPageInspectorTargetProxy.h"
+#import "WebPageProxy.h"
+
+#if PLATFORM(MAC)
+
+namespace WebKit {
+
+void WebPageInspectorTargetProxy::platformActivate(String& error) const
+{
+    NSWindow* window = m_page.platformWindow();
+    [window makeKeyAndOrderFront:nil];
+}
+
+} // namespace WebKit
+
+#endif
diff --git a/Source/WebKit/UIProcess/wpe/WebPageInspectorEmulationAgentWPE.cpp b/Source/WebKit/UIProcess/wpe/WebPageInspectorEmulationAgentWPE.cpp
new file mode 100644
index 00000000000..2fef19fd5ee
--- /dev/null
+++ b/Source/WebKit/UIProcess/wpe/WebPageInspectorEmulationAgentWPE.cpp
@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorEmulationAgent.h"
+
+#include "WebPageProxy.h"
+#include <wpe/wpe.h>
+
+namespace WebKit {
+
+void WebPageInspectorEmulationAgent::platformSetSize(String& error, int width, int height)
+{
+    struct wpe_view_backend* backend = m_page.viewBackend();
+    wpe_view_backend_dispatch_set_size(backend, width, height);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/wpe/WebPageInspectorInputAgentWPE.cpp b/Source/WebKit/UIProcess/wpe/WebPageInspectorInputAgentWPE.cpp
new file mode 100644
index 00000000000..bbcba6f0a65
--- /dev/null
+++ b/Source/WebKit/UIProcess/wpe/WebPageInspectorInputAgentWPE.cpp
@@ -0,0 +1,76 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorInputAgent.h"
+
+#include "NativeWebKeyboardEvent.h"
+#include "WebPageProxy.h"
+#include <WebCore/PlatformKeyboardEvent.h>
+#include <wpe/wpe.h>
+
+namespace WebKit {
+
+void WebPageInspectorInputAgent::platformDispatchKeyEvent(String& error, const String& type, const String& keyRef)
+{
+}
+
+static unsigned toWPEButton(WebMouseEvent::Button button)
+{
+    switch (button) {
+    case WebMouseEvent::NoButton:
+    case WebMouseEvent::LeftButton:
+        return 1;
+    case WebMouseEvent::MiddleButton:
+        return 3;
+    case WebMouseEvent::RightButton:
+        return 2;
+    }
+    return 1;
+}
+
+static unsigned toWPEModifiers(OptionSet<WebEvent::Modifier> modifiers)
+{
+    unsigned result = 0;
+    if (modifiers.contains(WebEvent::Modifier::ControlKey))
+        result |= wpe_input_keyboard_modifier_control;
+    if (modifiers.contains(WebEvent::Modifier::ShiftKey))
+        result |= wpe_input_keyboard_modifier_shift;
+    if (modifiers.contains(WebEvent::Modifier::AltKey))
+        result |= wpe_input_keyboard_modifier_alt;
+    if (modifiers.contains(WebEvent::Modifier::CapsLockKey))
+       fprintf(stderr, "Unsupported modifier CapsLock will be ignored.\n");
+    return result;
+}
+
+void WebPageInspectorInputAgent::platformDispatchKeyEvent(WebKeyboardEvent::Type type, const String& text, const String& unmodifiedText, const String& key, const String& code, int windowsVirtualKeyCode, int nativeVirtualKeyCode, bool isAutoRepeat, bool isKeypad, bool isSystemKey, OptionSet<WebEvent::Modifier> modifiers, Vector<String>& macCommands, WallTime timestamp)
+{
+    unsigned keyCode = WebCore::PlatformKeyboardEvent::WPEKeyCodeForWindowsKeyCode(windowsVirtualKeyCode);
+    struct wpe_input_xkb_keymap_entry* entries;
+    uint32_t entriesCount;
+    fprintf(stderr, "platformDispatchKeyEvent %s => %d\n", key.ascii().data(), keyCode);
+    wpe_input_xkb_context_get_entries_for_key_code(wpe_input_xkb_context_get_default(), keyCode, &entries, &entriesCount);
+    bool pressed = type == WebKeyboardEvent::KeyDown;
+    struct wpe_input_keyboard_event event = { 0, keyCode, entriesCount ? entries[0].hardware_key_code : 0, pressed, toWPEModifiers(modifiers) };
+    // event.time = timestamp.secondsSinceEpoch().milliseconds();
+    wpe_view_backend_dispatch_keyboard_event(m_page.viewBackend(), &event);
+    free(entries);
+}
+
+void WebPageInspectorInputAgent::platformDispatchMouseEvent(WebMouseEvent::Type type, int x, int y, WebMouseEvent::Button button, OptionSet<WebEvent::Modifier> modifiers)
+{
+    wpe_input_pointer_event_type eventType = wpe_input_pointer_event_type_null;
+    uint32_t eventButton = 0;
+    uint32_t state = 0;
+    if (type == WebEvent::MouseDown || type == WebEvent::MouseUp) {
+        eventType = wpe_input_pointer_event_type_button;
+        state = (type == WebEvent::MouseDown);
+        eventButton = toWPEButton(button);
+    } else if (type == WebEvent::MouseMove) {
+        eventType = wpe_input_pointer_event_type_motion;
+    }
+    struct wpe_input_pointer_event event { eventType, 0, x, y, eventButton, state, toWPEModifiers(modifiers) };
+    wpe_view_backend_dispatch_pointer_event(m_page.viewBackend(), &event);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/UIProcess/wpe/WebPageInspectorTargetProxyWPE.cpp b/Source/WebKit/UIProcess/wpe/WebPageInspectorTargetProxyWPE.cpp
new file mode 100644
index 00000000000..74dace1cc7c
--- /dev/null
+++ b/Source/WebKit/UIProcess/wpe/WebPageInspectorTargetProxyWPE.cpp
@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "config.h"
+#include "WebPageInspectorTargetProxy.h"
+
+#include "WebPageProxy.h"
+#include <wpe/wpe.h>
+
+namespace WebKit {
+
+void WebPageInspectorTargetProxy::platformActivate(String& error) const
+{
+    struct wpe_view_backend* backend = m_page.viewBackend();
+    wpe_view_backend_add_activity_state(backend, wpe_view_activity_state_visible | wpe_view_activity_state_focused | wpe_view_activity_state_in_window);
+}
+
+} // namespace WebKit
diff --git a/Source/WebKit/WebKit.xcodeproj/project.pbxproj b/Source/WebKit/WebKit.xcodeproj/project.pbxproj
index 5c85fc15494..f9584b35e8f 100644
--- a/Source/WebKit/WebKit.xcodeproj/project.pbxproj
+++ b/Source/WebKit/WebKit.xcodeproj/project.pbxproj
@@ -1695,6 +1695,20 @@
 		CEE4AE2B1A5DCF430002F49B /* UIKitSPI.h in Headers */ = {isa = PBXBuildFile; fileRef = CEE4AE2A1A5DCF430002F49B /* UIKitSPI.h */; };
 		D3B9484711FF4B6500032B39 /* WebPopupMenu.h in Headers */ = {isa = PBXBuildFile; fileRef = D3B9484311FF4B6500032B39 /* WebPopupMenu.h */; };
 		D3B9484911FF4B6500032B39 /* WebSearchPopupMenu.h in Headers */ = {isa = PBXBuildFile; fileRef = D3B9484511FF4B6500032B39 /* WebSearchPopupMenu.h */; };
+		D71A94322370E025002C4D9E /* InspectorBrowserAgentClientMac.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94302370E025002C4D9E /* InspectorBrowserAgentClientMac.h */; };
+		D71A94342370E07A002C4D9E /* InspectorBrowserAgentClient.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94332370E07A002C4D9E /* InspectorBrowserAgentClient.h */; };
+		D71A94382370F032002C4D9E /* BrowserInspectorController.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94372370F032002C4D9E /* BrowserInspectorController.h */; };
+		D71A943A2370F061002C4D9E /* RemoteInspectorPipe.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94392370F060002C4D9E /* RemoteInspectorPipe.h */; };
+		D71A94412371F67E002C4D9E /* WebPageInspectorTargetProxy.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A943E2371F67E002C4D9E /* WebPageInspectorTargetProxy.h */; };
+		D71A94422371F67E002C4D9E /* WebPageInspectorEmulationAgent.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A943F2371F67E002C4D9E /* WebPageInspectorEmulationAgent.h */; };
+		D71A94432371F67E002C4D9E /* WebPageInspectorInputAgent.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94402371F67E002C4D9E /* WebPageInspectorInputAgent.h */; };
+		D71A944A2372290B002C4D9E /* _WKBrowserInspector.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A94492372290B002C4D9E /* _WKBrowserInspector.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		D71A944C237239FB002C4D9E /* BrowserInspectorPipe.h in Headers */ = {isa = PBXBuildFile; fileRef = D71A944B237239FB002C4D9E /* BrowserInspectorPipe.h */; };
+		D76D6888238DBD81008D314B /* InspectorDialogAgent.h in Headers */ = {isa = PBXBuildFile; fileRef = D76D6887238DBD80008D314B /* InspectorDialogAgent.h */; };
+		D79902B1236E9404005D6F7E /* WebPageInspectorEmulationAgentMac.mm in Sources */ = {isa = PBXBuildFile; fileRef = D79902AE236E9404005D6F7E /* WebPageInspectorEmulationAgentMac.mm */; };
+		D79902B2236E9404005D6F7E /* WebPageInspectorTargetProxyMac.mm in Sources */ = {isa = PBXBuildFile; fileRef = D79902AF236E9404005D6F7E /* WebPageInspectorTargetProxyMac.mm */; };
+		D79902B3236E9404005D6F7E /* WebPageInspectorInputAgentMac.mm in Sources */ = {isa = PBXBuildFile; fileRef = D79902B0236E9404005D6F7E /* WebPageInspectorInputAgentMac.mm */; };
+		D7EB04E72372A73B00F744CE /* InspectorBrowserAgentClientMac.mm in Sources */ = {isa = PBXBuildFile; fileRef = D7EB04E62372A73B00F744CE /* InspectorBrowserAgentClientMac.mm */; };
 		E105FE5418D7B9DE008F57A8 /* EditingRange.h in Headers */ = {isa = PBXBuildFile; fileRef = E105FE5318D7B9DE008F57A8 /* EditingRange.h */; };
 		E11D35AE16B63D1B006D23D7 /* com.apple.WebProcess.sb in Resources */ = {isa = PBXBuildFile; fileRef = E1967E37150AB5E200C73169 /* com.apple.WebProcess.sb */; };
 		E14A954A16E016A40068DE82 /* NetworkProcessPlatformStrategies.h in Headers */ = {isa = PBXBuildFile; fileRef = E14A954816E016A40068DE82 /* NetworkProcessPlatformStrategies.h */; };
@@ -4839,6 +4853,21 @@
 		D3B9484311FF4B6500032B39 /* WebPopupMenu.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WebPopupMenu.h; sourceTree = "<group>"; };
 		D3B9484411FF4B6500032B39 /* WebSearchPopupMenu.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = WebSearchPopupMenu.cpp; sourceTree = "<group>"; };
 		D3B9484511FF4B6500032B39 /* WebSearchPopupMenu.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WebSearchPopupMenu.h; sourceTree = "<group>"; };
+		D71A942C2370DF81002C4D9E /* WKBrowserInspector.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WKBrowserInspector.h; sourceTree = "<group>"; };
+		D71A94302370E025002C4D9E /* InspectorBrowserAgentClientMac.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InspectorBrowserAgentClientMac.h; sourceTree = "<group>"; };
+		D71A94332370E07A002C4D9E /* InspectorBrowserAgentClient.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InspectorBrowserAgentClient.h; sourceTree = "<group>"; };
+		D71A94372370F032002C4D9E /* BrowserInspectorController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BrowserInspectorController.h; sourceTree = "<group>"; };
+		D71A94392370F060002C4D9E /* RemoteInspectorPipe.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RemoteInspectorPipe.h; sourceTree = "<group>"; };
+		D71A943E2371F67E002C4D9E /* WebPageInspectorTargetProxy.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WebPageInspectorTargetProxy.h; sourceTree = "<group>"; };
+		D71A943F2371F67E002C4D9E /* WebPageInspectorEmulationAgent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WebPageInspectorEmulationAgent.h; sourceTree = "<group>"; };
+		D71A94402371F67E002C4D9E /* WebPageInspectorInputAgent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WebPageInspectorInputAgent.h; sourceTree = "<group>"; };
+		D71A94492372290B002C4D9E /* _WKBrowserInspector.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = _WKBrowserInspector.h; sourceTree = "<group>"; };
+		D71A944B237239FB002C4D9E /* BrowserInspectorPipe.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BrowserInspectorPipe.h; sourceTree = "<group>"; };
+		D76D6887238DBD80008D314B /* InspectorDialogAgent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = InspectorDialogAgent.h; sourceTree = "<group>"; };
+		D79902AE236E9404005D6F7E /* WebPageInspectorEmulationAgentMac.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = WebPageInspectorEmulationAgentMac.mm; sourceTree = "<group>"; };
+		D79902AF236E9404005D6F7E /* WebPageInspectorTargetProxyMac.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = WebPageInspectorTargetProxyMac.mm; sourceTree = "<group>"; };
+		D79902B0236E9404005D6F7E /* WebPageInspectorInputAgentMac.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = WebPageInspectorInputAgentMac.mm; sourceTree = "<group>"; };
+		D7EB04E62372A73B00F744CE /* InspectorBrowserAgentClientMac.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = InspectorBrowserAgentClientMac.mm; sourceTree = "<group>"; };
 		DF58C6311371AC5800F9A37C /* NativeWebWheelEvent.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = NativeWebWheelEvent.h; sourceTree = "<group>"; };
 		DF58C6351371ACA000F9A37C /* NativeWebWheelEventMac.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = NativeWebWheelEventMac.mm; sourceTree = "<group>"; };
 		E105FE5318D7B9DE008F57A8 /* EditingRange.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = EditingRange.h; sourceTree = "<group>"; };
@@ -6608,6 +6637,7 @@
 		37C4C08318149C2A003688B9 /* Cocoa */ = {
 			isa = PBXGroup;
 			children = (
+				D71A94492372290B002C4D9E /* _WKBrowserInspector.h */,
 				1A43E826188F38E2009E4D30 /* Deprecated */,
 				37A5E01218BBF937000A081E /* _WKActivatedElementInfo.h */,
 				37A5E01118BBF937000A081E /* _WKActivatedElementInfo.mm */,
@@ -8100,6 +8130,14 @@
 		BC032DC310F438260058C15A /* UIProcess */ = {
 			isa = PBXGroup;
 			children = (
+				D76D6887238DBD80008D314B /* InspectorDialogAgent.h */,
+				D71A944B237239FB002C4D9E /* BrowserInspectorPipe.h */,
+				D71A943F2371F67E002C4D9E /* WebPageInspectorEmulationAgent.h */,
+				D71A94402371F67E002C4D9E /* WebPageInspectorInputAgent.h */,
+				D71A943E2371F67E002C4D9E /* WebPageInspectorTargetProxy.h */,
+				D71A94392370F060002C4D9E /* RemoteInspectorPipe.h */,
+				D71A94372370F032002C4D9E /* BrowserInspectorController.h */,
+				D71A94332370E07A002C4D9E /* InspectorBrowserAgentClient.h */,
 				BC032DC410F4387C0058C15A /* API */,
 				512F588D12A8836F00629530 /* Authentication */,
 				9955A6E81C79809000EB6A93 /* Automation */,
@@ -8381,6 +8419,7 @@
 		BC0C376610F807660076D7CB /* C */ = {
 			isa = PBXGroup;
 			children = (
+				D71A942C2370DF81002C4D9E /* WKBrowserInspector.h */,
 				5123CF18133D25E60056F800 /* cg */,
 				6EE849C41368D9040038D481 /* mac */,
 				BCB63477116BF10600603215 /* WebKit2_C.h */,
@@ -8978,6 +9017,11 @@
 		BCCF085C113F3B7500C650C5 /* mac */ = {
 			isa = PBXGroup;
 			children = (
+				D7EB04E62372A73B00F744CE /* InspectorBrowserAgentClientMac.mm */,
+				D71A94302370E025002C4D9E /* InspectorBrowserAgentClientMac.h */,
+				D79902AE236E9404005D6F7E /* WebPageInspectorEmulationAgentMac.mm */,
+				D79902B0236E9404005D6F7E /* WebPageInspectorInputAgentMac.mm */,
+				D79902AF236E9404005D6F7E /* WebPageInspectorTargetProxyMac.mm */,
 				B878B613133428DC006888E9 /* CorrectionPanel.h */,
 				B878B614133428DC006888E9 /* CorrectionPanel.mm */,
 				C1817362205844A900DFDA65 /* DisplayLink.cpp */,
@@ -9670,6 +9714,7 @@
 				510F59101DDE296900412FF5 /* _WKIconLoadingDelegate.h in Headers */,
 				37A64E5518F38E3C00EB30F1 /* _WKInputDelegate.h in Headers */,
 				5CAFDE452130846300B1F7E1 /* _WKInspector.h in Headers */,
+				D71A944A2372290B002C4D9E /* _WKBrowserInspector.h in Headers */,
 				5CAFDE472130846A00B1F7E1 /* _WKInspectorInternal.h in Headers */,
 				9979CA58237F49F10039EC05 /* _WKInspectorPrivate.h in Headers */,
 				A5C0F0AB2000658200536536 /* _WKInspectorWindow.h in Headers */,
@@ -9787,6 +9832,7 @@
 				7C89D2981A6753B2003A5FDE /* APIPageConfiguration.h in Headers */,
 				1AC1336C18565C7A00F3EC05 /* APIPageHandle.h in Headers */,
 				1AFDD3151891B54000153970 /* APIPolicyClient.h in Headers */,
+				D71A94382370F032002C4D9E /* BrowserInspectorController.h in Headers */,
 				7CE4D2201A4914CA00C7F152 /* APIProcessPoolConfiguration.h in Headers */,
 				49BCA19223A177660028A836 /* APIResourceLoadStatisticsFirstParty.h in Headers */,
 				49BCA19723A1930D0028A836 /* APIResourceLoadStatisticsThirdParty.h in Headers */,
@@ -9908,6 +9954,7 @@
 				BC06F43A12DBCCFB002D78DE /* GeolocationPermissionRequestProxy.h in Headers */,
 				2DA944A41884E4F000ED86DB /* GestureTypes.h in Headers */,
 				2DA049B8180CCD0A00AAFA9E /* GraphicsLayerCARemote.h in Headers */,
+				D71A94342370E07A002C4D9E /* InspectorBrowserAgentClient.h in Headers */,
 				C0CE72AD1247E78D00BC0EC4 /* HandleMessage.h in Headers */,
 				1AC75A1B1B3368270056745B /* HangDetectionDisabler.h in Headers */,
 				57AC8F50217FEED90055438C /* HidConnection.h in Headers */,
@@ -10032,8 +10079,10 @@
 				41DC45961E3D6E2200B11F51 /* NetworkRTCProvider.h in Headers */,
 				413075AB1DE85F330039EC69 /* NetworkRTCSocket.h in Headers */,
 				5C20CBA01BB1ECD800895BB1 /* NetworkSession.h in Headers */,
+				D71A94422371F67E002C4D9E /* WebPageInspectorEmulationAgent.h in Headers */,
 				532159551DBAE7290054AA3C /* NetworkSessionCocoa.h in Headers */,
 				417915B92257046F00D6F97E /* NetworkSocketChannel.h in Headers */,
+				D71A943A2370F061002C4D9E /* RemoteInspectorPipe.h in Headers */,
 				570DAAC22303730300E8FC04 /* NfcConnection.h in Headers */,
 				570DAAAE23026F5C00E8FC04 /* NfcService.h in Headers */,
 				31A2EC5614899C0900810D71 /* NotificationPermissionRequest.h in Headers */,
@@ -10115,6 +10164,7 @@
 				CD2865EE2255562000606AC7 /* ProcessTaskStateObserver.h in Headers */,
 				463FD4821EB94EC000A2982C /* ProcessTerminationReason.h in Headers */,
 				86E67A251910B9D100004AB7 /* ProcessThrottler.h in Headers */,
+				D71A944C237239FB002C4D9E /* BrowserInspectorPipe.h in Headers */,
 				83048AE61ACA45DC0082C832 /* ProcessThrottlerClient.h in Headers */,
 				A1E688701F6E2BAB007006A6 /* QuarantineSPI.h in Headers */,
 				57FD318222B3515E008D0E8B /* RedirectSOAuthorizationSession.h in Headers */,
@@ -10280,6 +10330,7 @@
 				F430E94422473DFF005FE053 /* WebContentMode.h in Headers */,
 				31A505FA1680025500A930EB /* WebContextClient.h in Headers */,
 				BC09B8F9147460F7005F5625 /* WebContextConnectionClient.h in Headers */,
+				D71A94412371F67E002C4D9E /* WebPageInspectorTargetProxy.h in Headers */,
 				BCDE059B11CDA8AE00E41AF1 /* WebContextInjectedBundleClient.h in Headers */,
 				51871B5C127CB89D00F76232 /* WebContextMenu.h in Headers */,
 				BC032D7710F4378D0058C15A /* WebContextMenuClient.h in Headers */,
@@ -10518,6 +10569,7 @@
 				BCD25F1711D6BDE100169B0E /* WKBundleFrame.h in Headers */,
 				BCF049E611FE20F600F86A58 /* WKBundleFramePrivate.h in Headers */,
 				BC49862F124D18C100D834E1 /* WKBundleHitTestResult.h in Headers */,
+				D71A94432371F67E002C4D9E /* WebPageInspectorInputAgent.h in Headers */,
 				BC204EF211C83EC8008F3375 /* WKBundleInitialize.h in Headers */,
 				65B86F1E12F11DE300B7DD8A /* WKBundleInspector.h in Headers */,
 				1A8B66B41BC45B010082DF77 /* WKBundleMac.h in Headers */,
@@ -10566,6 +10618,7 @@
 				5C795D71229F3757003FF1C4 /* WKContextMenuElementInfoPrivate.h in Headers */,
 				51A555F6128C6C47009ABCEC /* WKContextMenuItem.h in Headers */,
 				51A55601128C6D92009ABCEC /* WKContextMenuItemTypes.h in Headers */,
+				D76D6888238DBD81008D314B /* InspectorDialogAgent.h in Headers */,
 				A1EA02381DABFF7E0096021F /* WKContextMenuListener.h in Headers */,
 				BCC938E11180DE440085E5FE /* WKContextPrivate.h in Headers */,
 				9FB5F395169E6A80002C25BF /* WKContextPrivateMac.h in Headers */,
@@ -10715,6 +10768,7 @@
 				1AB8A1F818400BB800E9AE69 /* WKPageContextMenuClient.h in Headers */,
 				8372DB251A674C8F00C697C5 /* WKPageDiagnosticLoggingClient.h in Headers */,
 				1AB8A1F418400B8F00E9AE69 /* WKPageFindClient.h in Headers */,
+				D71A94322370E025002C4D9E /* InspectorBrowserAgentClientMac.h in Headers */,
 				1AB8A1F618400B9D00E9AE69 /* WKPageFindMatchesClient.h in Headers */,
 				1AB8A1F018400B0000E9AE69 /* WKPageFormClient.h in Headers */,
 				BC7B633712A45ABA00D174A4 /* WKPageGroup.h in Headers */,
@@ -11746,6 +11800,7 @@
 				2D92A781212B6A7100F493FD /* MessageReceiverMap.cpp in Sources */,
 				2D92A782212B6A7100F493FD /* MessageSender.cpp in Sources */,
 				2D92A77A212B6A6100F493FD /* Module.cpp in Sources */,
+				D79902B1236E9404005D6F7E /* WebPageInspectorEmulationAgentMac.mm in Sources */,
 				57B826452304F14000B72EB0 /* NearFieldSoftLink.mm in Sources */,
 				2D913443212CF9F000128AFD /* NetscapeBrowserFuncs.cpp in Sources */,
 				2D913444212CF9F000128AFD /* NetscapePlugin.cpp in Sources */,
@@ -11770,6 +11825,7 @@
 				1A2D8439127F65D5001EB962 /* NPObjectMessageReceiverMessageReceiver.cpp in Sources */,
 				2D92A792212B6AD400F493FD /* NPObjectProxy.cpp in Sources */,
 				2D92A793212B6AD400F493FD /* NPRemoteObjectMap.cpp in Sources */,
+				D7EB04E72372A73B00F744CE /* InspectorBrowserAgentClientMac.mm in Sources */,
 				2D913447212CF9F000128AFD /* NPRuntimeObjectMap.cpp in Sources */,
 				2D913448212CF9F000128AFD /* NPRuntimeUtilities.cpp in Sources */,
 				2D92A794212B6AD400F493FD /* NPVariantData.cpp in Sources */,
@@ -11811,11 +11867,13 @@
 				A1ADAFB62368E6A8009CB776 /* SharedMemory.cpp in Sources */,
 				2DE6943D18BD2A68005C15E5 /* SmartMagnificationControllerMessageReceiver.cpp in Sources */,
 				1A334DED16DE8F88006A8E38 /* StorageAreaMapMessageReceiver.cpp in Sources */,
+				D79902B3236E9404005D6F7E /* WebPageInspectorInputAgentMac.mm in Sources */,
 				9368EEDE2303A90200BDB11A /* StorageManagerSetMessageReceiver.cpp in Sources */,
 				2D92A783212B6A7100F493FD /* StringReference.cpp in Sources */,
 				2D11B7512126A282006F8878 /* UnifiedSource1-mm.mm in Sources */,
 				2D11B7522126A282006F8878 /* UnifiedSource1.cpp in Sources */,
 				2D11B7542126A282006F8878 /* UnifiedSource2.cpp in Sources */,
+				D79902B2236E9404005D6F7E /* WebPageInspectorTargetProxyMac.mm in Sources */,
 				2D11B7532126A282006F8878 /* UnifiedSource2-mm.mm in Sources */,
 				2D11B7562126A282006F8878 /* UnifiedSource3.cpp in Sources */,
 				2D11B7552126A282006F8878 /* UnifiedSource3-mm.mm in Sources */,
diff --git a/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.cpp b/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.cpp
index a70f6fd5209..f02e5c774a4 100644
--- a/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.cpp
+++ b/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.cpp
@@ -26,6 +26,8 @@
 #include "config.h"
 #include "WebPageInspectorTarget.h"
 
+#include "FrameInfoData.h"
+#include "WebFrame.h"
 #include "WebPage.h"
 #include "WebPageInspectorTargetFrontendChannel.h"
 #include <WebCore/InspectorController.h>
@@ -45,6 +47,11 @@ String WebPageInspectorTarget::identifier() const
     return toTargetID(m_page.identifier());
 }
 
+String WebPageInspectorTarget::url() const
+{
+    return m_page.mainWebFrame()->info().request.url().string();
+}
+
 void WebPageInspectorTarget::connect(Inspector::FrontendChannel::ConnectionType connectionType)
 {
     if (m_channel)
diff --git a/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.h b/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.h
index 6cbd7fad5ff..176c46f186b 100644
--- a/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.h
+++ b/Source/WebKit/WebProcess/WebPage/WebPageInspectorTarget.h
@@ -44,6 +44,7 @@ public:
     Inspector::InspectorTargetType type() const final { return Inspector::InspectorTargetType::Page; }
 
     String identifier() const final;
+    String url() const final;
 
     void connect(Inspector::FrontendChannel::ConnectionType) override;
     void disconnect() override;
diff --git a/Tools/MiniBrowser/gtk/BrowserWindow.h b/Tools/MiniBrowser/gtk/BrowserWindow.h
index 1570d65effb..456f96cf589 100644
--- a/Tools/MiniBrowser/gtk/BrowserWindow.h
+++ b/Tools/MiniBrowser/gtk/BrowserWindow.h
@@ -37,7 +37,7 @@ G_BEGIN_DECLS
 #define BROWSER_IS_WINDOW(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), BROWSER_TYPE_WINDOW))
 #define BROWSER_IS_WINDOW_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),  BROWSER_TYPE_WINDOW))
 #define BROWSER_WINDOW_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj),  BROWSER_TYPE_WINDOW, BrowserWindowClass))
-#define BROWSER_DEFAULT_URL            "http://www.webkitgtk.org/"
+#define BROWSER_DEFAULT_URL            "about:blank"
 #define BROWSER_ABOUT_SCHEME           "minibrowser-about"
 
 typedef struct _BrowserWindow        BrowserWindow;
diff --git a/Tools/MiniBrowser/gtk/main.c b/Tools/MiniBrowser/gtk/main.c
index 4c5147dcd38..c91a7baea1e 100644
--- a/Tools/MiniBrowser/gtk/main.c
+++ b/Tools/MiniBrowser/gtk/main.c
@@ -53,6 +53,7 @@ static const char *cookiesFile;
 static const char *cookiesPolicy;
 static const char *proxy;
 static gboolean darkMode;
+static gboolean inspectorPipe;
 static gboolean printVersion;
 
 typedef enum {
@@ -121,6 +122,7 @@ static const GOptionEntry commandLineOptions[] =
     { "ignore-tls-errors", 0, 0, G_OPTION_ARG_NONE, &ignoreTLSErrors, "Ignore TLS errors", NULL },
     { "content-filter", 0, 0, G_OPTION_ARG_FILENAME, &contentFilter, "JSON with content filtering rules", "FILE" },
     { "version", 'v', 0, G_OPTION_ARG_NONE, &printVersion, "Print the WebKitGTK version", NULL },
+    { "inspector-pipe", 0, 0, G_OPTION_ARG_NONE, &inspectorPipe, "Open pipe connection to the remote inspector", NULL },
     { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &uriArguments, 0, "[URL…]" },
     { 0, 0, 0, 0, 0, 0, 0 }
 };
@@ -498,6 +500,29 @@ static void filterSavedCallback(WebKitUserContentFilterStore *store, GAsyncResul
     g_main_loop_quit(data->mainLoop);
 }
 
+static WebKitWebView *createNewPage(WebKitBrowserInspector *browser_inspector, WebKitWebContext *context)
+{
+    WebKitWebView *newWebView = WEBKIT_WEB_VIEW(g_object_new(WEBKIT_TYPE_WEB_VIEW,
+        "web-context", context,
+        "is-ephemeral", webkit_web_context_is_ephemeral(context),
+        "is-controlled-by-automation", TRUE,
+        NULL));
+    GtkWidget *newWindow = browser_window_new(NULL, context);
+    browser_window_append_view(BROWSER_WINDOW(newWindow), newWebView);
+    gtk_widget_grab_focus(GTK_WIDGET(newWebView));
+    gtk_widget_show(GTK_WIDGET(newWindow));
+    webkit_web_view_load_uri(newWebView, "about:blank");
+    return newWebView;
+}
+
+static void configureBrowserInspectorPipe()
+{
+    WebKitBrowserInspector* browserInspector = webkit_browser_inspector_get_default();
+    g_signal_connect(browserInspector, "create-new-page", G_CALLBACK(createNewPage), NULL);
+
+    webkit_browser_inspector_initialize_pipe();
+}
+
 int main(int argc, char *argv[])
 {
 #if ENABLE_DEVELOPER_MODE
@@ -541,10 +566,21 @@ int main(int argc, char *argv[])
         return 0;
     }
 
-    WebKitWebsiteDataManager *manager = (privateMode || automationMode) ? webkit_website_data_manager_new_ephemeral() : webkit_website_data_manager_new(NULL);
+    WebKitWebsiteDataManager *manager;
+    if (inspectorPipe) {
+        manager = webkit_web_context_get_website_data_manager(webkit_web_context_get_default());
+    } else if (privateMode || automationMode) {
+        manager = webkit_website_data_manager_new_ephemeral();
+    } else {
+        manager = webkit_website_data_manager_new(NULL);
+    }
+
     WebKitWebContext *webContext = g_object_new(WEBKIT_TYPE_WEB_CONTEXT, "website-data-manager", manager, "process-swap-on-cross-site-navigation-enabled", TRUE, NULL);
     g_object_unref(manager);
 
+    if (inspectorPipe)
+        configureBrowserInspectorPipe();
+
     if (cookiesPolicy) {
         WebKitCookieManager *cookieManager = webkit_web_context_get_cookie_manager(webContext);
         GEnumClass *enumClass = g_type_class_ref(WEBKIT_TYPE_COOKIE_ACCEPT_POLICY);
diff --git a/Tools/MiniBrowser/mac/AppDelegate.h b/Tools/MiniBrowser/mac/AppDelegate.h
index 45ef1a6424e..30964dbd4cc 100644
--- a/Tools/MiniBrowser/mac/AppDelegate.h
+++ b/Tools/MiniBrowser/mac/AppDelegate.h
@@ -23,10 +23,23 @@
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#import <WebKit/_WKBrowserInspector.h>
+
 @class ExtensionManagerWindowController;
 
-@interface BrowserAppDelegate : NSObject <NSApplicationDelegate> {
+WK_CLASS_AVAILABLE(macos(10.14.0))
+@interface WebViewDialog : NSObject
+@property (nonatomic, strong) WKWebView *webView;
+@property (nonatomic, copy) void (^completionHandler)(BOOL accept, NSString* value);
+@end
+
+@interface BrowserAppDelegate : NSObject <NSApplicationDelegate, WKUIDelegate, _WKBrowserInspectorDelegate> {
     NSMutableSet *_browserWindowControllers;
+    NSMutableSet *_headlessWindows;
+    NSMutableSet *_browserContexts;
+    bool _headless;
+    NSMutableSet *_dialogs;
+    NSString* _initialURL;
     ExtensionManagerWindowController *_extensionManagerWindowController;
 
     IBOutlet NSMenuItem *_newWebKit1WindowItem;
diff --git a/Tools/MiniBrowser/mac/AppDelegate.m b/Tools/MiniBrowser/mac/AppDelegate.m
index b6af4ef724f..0afe6ceec4f 100644
--- a/Tools/MiniBrowser/mac/AppDelegate.m
+++ b/Tools/MiniBrowser/mac/AppDelegate.m
@@ -33,7 +33,9 @@
 #import <WebKit/WKProcessPoolPrivate.h>
 #import <WebKit/WKUserContentControllerPrivate.h>
 #import <WebKit/WKWebViewConfigurationPrivate.h>
+#import <WebKit/WKWebViewPrivate.h>
 #import <WebKit/WKWebsiteDataStorePrivate.h>
+#import <WebKit/WebNSURLExtras.h>
 #import <WebKit/WebKit.h>
 #import <WebKit/_WKExperimentalFeature.h>
 #import <WebKit/_WKInternalDebugFeature.h>
@@ -52,16 +54,53 @@ @interface NSApplication (TouchBar)
 @property (getter=isAutomaticCustomizeTouchBarMenuItemEnabled) BOOL automaticCustomizeTouchBarMenuItemEnabled;
 @end
 
+@implementation WebViewDialog
+@end
+
+enum {
+    _NSBackingStoreUnbuffered = 3
+};
+
+NSString* const ActivityReason = @"Batch headless process";
+const NSActivityOptions ActivityOptions =
+    (NSActivityUserInitiatedAllowingIdleSystemSleep |
+     NSActivityLatencyCritical) &
+    ~(NSActivitySuddenTerminationDisabled |
+    NSActivityAutomaticTerminationDisabled);
+
 @implementation BrowserAppDelegate
 
 - (id)init
 {
     self = [super init];
-    if (self) {
-        _browserWindowControllers = [[NSMutableSet alloc] init];
-        _extensionManagerWindowController = [[ExtensionManagerWindowController alloc] init];
+    if (!self)
+        return nil;
+
+    _initialURL = nil;
+    NSArray *arguments = [[NSProcessInfo processInfo] arguments];
+    NSRange subargs = NSMakeRange(1, [arguments count] - 1);
+    NSArray *subArray = [arguments subarrayWithRange:subargs];
+
+    for (NSString *argument in subArray) {
+        if (![argument hasPrefix:@"--"])
+            _initialURL = argument;
     }
 
+    _headless = [arguments containsObject: @"--headless"];
+    _browserContexts = [[NSMutableSet alloc] init];
+
+    if (_headless) {
+        _headlessWindows = [[NSMutableSet alloc] init];
+        [NSApp setActivationPolicy:NSApplicationActivationPolicyAccessory];
+        [[NSProcessInfo processInfo] beginActivityWithOptions:ActivityOptions
+                                                       reason:ActivityReason];
+        _dialogs = [[NSMutableSet alloc] init];
+    } else {
+        _extensionManagerWindowController = [[ExtensionManagerWindowController alloc] init];
+        _browserWindowControllers = [[NSMutableSet alloc] init];
+    }
+    if ([arguments containsObject: @"--inspector-pipe"])
+        [_WKBrowserInspector initializeRemoteInspectorPipe:self headless:_headless];
     return self;
 }
 
@@ -88,7 +127,7 @@ - (void)awakeFromNib
         configuration.networkCacheSpeculativeValidationEnabled = YES;
         dataStore = [[WKWebsiteDataStore alloc] _initWithConfiguration:configuration];
     }
-    
+
     return dataStore;
 }
 
@@ -103,13 +142,18 @@ - (void)awakeFromNib
         configuration.preferences._developerExtrasEnabled = YES;
         configuration.preferences._mediaDevicesEnabled = YES;
         configuration.preferences._mockCaptureDevicesEnabled = YES;
+        configuration.preferences._hiddenPageDOMTimerThrottlingEnabled = NO;
+        configuration.preferences._hiddenPageDOMTimerThrottlingAutoIncreases = NO;
+        configuration.preferences._pageVisibilityBasedProcessSuppressionEnabled = NO;
+        configuration.preferences._domTimersThrottlingEnabled = NO;
+        configuration.preferences._requestAnimationFrameEnabled = YES;
 
         _WKProcessPoolConfiguration *processConfiguration = [[[_WKProcessPoolConfiguration alloc] init] autorelease];
         if ([SettingsController shared].perWindowWebProcessesDisabled)
             processConfiguration.usesSingleWebProcess = YES;
         if ([SettingsController shared].processSwapOnWindowOpenWithOpenerEnabled)
             processConfiguration.processSwapsOnWindowOpenWithOpener = true;
-        
+
         configuration.processPool = [[[WKProcessPool alloc] _initWithConfiguration:processConfiguration] autorelease];
 
         NSArray<_WKExperimentalFeature *> *experimentalFeatures = [WKPreferences _experimentalFeatures];
@@ -145,6 +189,9 @@ - (void)awakeFromNib
 
 - (BrowserWindowController *)createBrowserWindowController:(id)sender
 {
+    if (_headless)
+        return nil;
+
     BrowserWindowController *controller = nil;
     BOOL useWebKit2 = NO;
     BOOL makeEditable = NO;
@@ -158,9 +205,9 @@ - (BrowserWindowController *)createBrowserWindowController:(id)sender
     }
 
     if (!useWebKit2)
-        controller = [[WK1BrowserWindowController alloc] initWithWindowNibName:@"BrowserWindow"];
+        controller = [[[WK1BrowserWindowController alloc] initWithWindowNibName:@"BrowserWindow"] autorelease];
     else
-        controller = [[WK2BrowserWindowController alloc] initWithConfiguration:defaultConfiguration()];
+        controller = [[[WK2BrowserWindowController alloc] initWithConfiguration:defaultConfiguration()] autorelease];
 
     if (makeEditable)
         controller.editable = YES;
@@ -185,6 +232,9 @@ - (IBAction)newWindow:(id)sender
 
 - (IBAction)newPrivateWindow:(id)sender
 {
+    if (_headless)
+        return;
+
     WKWebViewConfiguration *privateConfiguraton = [defaultConfiguration() copy];
     privateConfiguraton.websiteDataStore = [WKWebsiteDataStore nonPersistentDataStore];
 
@@ -214,16 +264,19 @@ - (void)browserWindowWillClose:(NSWindow *)window
 
 - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
 {
+    if (_headless) {
+        [self createNewPage:0];
+        return;
+    }
+
     WebHistory *webHistory = [[WebHistory alloc] init];
     [WebHistory setOptionalSharedHistory:webHistory];
     [webHistory release];
 
     [self _updateNewWindowKeyEquivalents];
-
-    if ([SettingsController shared].createEditorByDefault)
-        [self newEditorWindow:self];
-    else
+    if (!_initialURL)
         [self newWindow:self];
+    _initialURL = nil;
 }
 
 - (BrowserWindowController *)frontmostBrowserWindowController
@@ -249,12 +302,15 @@ - (BOOL)application:(NSApplication *)theApplication openFile:(NSString *)filenam
         return NO;
 
     [controller.window makeKeyAndOrderFront:self];
-    [controller loadURLString:[NSURL fileURLWithPath:filename].absoluteString];
+    [controller loadURLString:_initialURL ? _initialURL : [NSURL fileURLWithPath:filename].absoluteString];
     return YES;
 }
 
 - (IBAction)openDocument:(id)sender
 {
+    if (_headless)
+        return;
+
     BrowserWindowController *browserWindowController = [self frontmostBrowserWindowController];
 
     if (browserWindowController) {
@@ -284,6 +340,9 @@ - (IBAction)openDocument:(id)sender
 
 - (void)didChangeSettings
 {
+    if (_headless)
+        return;
+
     [self _updateNewWindowKeyEquivalents];
 
     // Let all of the BrowserWindowControllers know that a setting changed, so they can attempt to dynamically update.
@@ -312,6 +371,8 @@ - (void)_updateNewWindowKeyEquivalents
 
 - (IBAction)showExtensionsManager:(id)sender
 {
+    if (_headless)
+        return;
     [_extensionManagerWindowController showWindow:sender];
 }
 
@@ -345,4 +406,148 @@ - (IBAction)clearDefaultStoreWebsiteData:(id)sender
     }];
 }
 
+#pragma mark WKBrowserInspectorDelegate
+
+- (WKWebViewConfiguration *) sessionConfiguration:(uint64_t)sessionID
+{
+    for (_WKBrowserContext *browserContext in _browserContexts) {
+        if ([[browserContext dataStore] sessionID] != sessionID)
+            continue;
+        WKWebViewConfiguration *configuration = [[defaultConfiguration() copy] autorelease];
+        configuration.websiteDataStore = [browserContext dataStore];
+        configuration.processPool = [browserContext processPool];
+        return configuration;
+    }
+    return defaultConfiguration();
+}
+
+- (WKWebView *)createNewPage:(uint64_t)sessionID
+{
+    if (_headless)
+        return [self createHeadlessPage:sessionID];
+
+    WKWebViewConfiguration *configuration = [self sessionConfiguration:sessionID];
+    WK2BrowserWindowController *controller = [[[WK2BrowserWindowController alloc] initWithConfiguration:configuration] autorelease];
+    if (!controller)
+        return nil;
+    [[controller window] makeKeyAndOrderFront:nil];
+    [_browserWindowControllers addObject:controller];
+    [controller loadURLString:[SettingsController shared].defaultURL];
+    return [controller webView];
+}
+
+- (WKWebView *)createHeadlessWebView:(WKWebViewConfiguration *)configuration
+{
+    NSRect rect = NSMakeRect(0, 0, 1024, 768);
+    NSScreen *firstScreen = [[NSScreen screens] objectAtIndex:0];
+    NSRect windowRect = NSOffsetRect(rect, -10000, [firstScreen frame].size.height - rect.size.height + 10000);
+    NSWindow* window = [[NSWindow alloc] initWithContentRect:windowRect styleMask:NSWindowStyleMaskBorderless backing:(NSBackingStoreType)_NSBackingStoreUnbuffered defer:YES];
+
+    WKWebView* webView = [[WKWebView alloc] initWithFrame:[window.contentView bounds] configuration:configuration];
+    webView._windowOcclusionDetectionEnabled = NO;
+    if (!webView)
+        return nil;
+
+    webView.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
+    [window.contentView addSubview:webView];
+    NSURL *url = [NSURL _webkit_URLWithUserTypedString:_initialURL ? _initialURL : @"about:blank"];
+    _initialURL = nil;
+    [webView loadRequest:[NSURLRequest requestWithURL:url]];
+    [_headlessWindows addObject:window];
+    webView.UIDelegate = self;
+    return [webView autorelease];
+}
+
+- (WKWebView *)createHeadlessPage:(uint64_t)sessionID
+{
+    WKWebViewConfiguration *configuration = [self sessionConfiguration:sessionID];
+    return [self createHeadlessWebView:configuration];
+}
+
+- (_WKBrowserContext *)createBrowserContext
+{
+    _WKBrowserContext *browserContext = [[_WKBrowserContext alloc] init];
+    _WKProcessPoolConfiguration *processConfiguration = [[[_WKProcessPoolConfiguration alloc] init] autorelease];
+    browserContext.dataStore = [WKWebsiteDataStore nonPersistentDataStore];
+    browserContext.processPool = [[[WKProcessPool alloc] _initWithConfiguration:processConfiguration] autorelease];
+    [_browserContexts addObject:browserContext];
+    return browserContext;
+}
+
+- (void)deleteBrowserContext:(uint64_t)sessionID
+{
+    for (_WKBrowserContext *browserContext in _browserContexts) {
+        if ([[browserContext dataStore] sessionID] != sessionID)
+            continue;
+        [_browserContexts removeObject:browserContext];
+        return;
+    }
+}
+
+- (void)quit
+{
+    [NSApp performSelector:@selector(terminate:) withObject:nil afterDelay:0.0];
+}
+
+#pragma mark WKUIDelegate
+
+- (void)webViewDidClose:(WKWebView *)webView {
+    for (NSWindow *window in _headlessWindows) {
+        if (webView.window != window)
+            continue;
+        [webView removeFromSuperview];
+        [window close];
+        [_headlessWindows removeObject:window];
+        break;
+    }
+}
+
+- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler
+{
+    WebViewDialog* dialog = [[WebViewDialog alloc] autorelease];
+    dialog.webView = webView;
+    dialog.completionHandler = ^void (BOOL accept, NSString* value) {
+        completionHandler();
+        [_dialogs removeObject:dialog];
+    };
+    [_dialogs addObject:dialog];
+}
+
+- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler
+{
+    WebViewDialog* dialog = [[WebViewDialog alloc] autorelease];
+    dialog.webView = webView;
+    dialog.completionHandler = ^void (BOOL accept, NSString* value) {
+        completionHandler(accept);
+        [_dialogs removeObject:dialog];
+    };
+    [_dialogs addObject:dialog];
+}
+
+- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString *result))completionHandler
+{
+    WebViewDialog* dialog = [[WebViewDialog alloc] autorelease];
+    dialog.webView = webView;
+    dialog.completionHandler = ^void (BOOL accept, NSString* value) {
+        completionHandler(accept && value ? value : nil);
+        [_dialogs removeObject:dialog];
+    };
+    [_dialogs addObject:dialog];
+}
+
+- (void)webView:(WKWebView *)webView handleJavaScriptDialog:(BOOL)accept value:(NSString *)value
+{
+    for (WebViewDialog *dialog in _dialogs) {
+        if (dialog.webView != webView)
+            continue;
+        dialog.completionHandler(accept, value);
+        break;
+    }
+}
+
+- (nullable WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures
+{
+    return [self createHeadlessWebView:configuration];
+}
+
 @end
diff --git a/Tools/MiniBrowser/mac/SettingsController.m b/Tools/MiniBrowser/mac/SettingsController.m
index 4a3a65505cd..2e48e0a52bb 100644
--- a/Tools/MiniBrowser/mac/SettingsController.m
+++ b/Tools/MiniBrowser/mac/SettingsController.m
@@ -31,7 +31,7 @@
 #import <WebKit/_WKExperimentalFeature.h>
 #import <WebKit/_WKInternalDebugFeature.h>
 
-static NSString * const defaultURL = @"http://www.webkit.org/";
+static NSString * const defaultURL = @"about:blank";
 static NSString * const DefaultURLPreferenceKey = @"DefaultURL";
 
 static NSString * const UseWebKit2ByDefaultPreferenceKey = @"UseWebKit2ByDefault";
diff --git a/Tools/MiniBrowser/mac/WK2BrowserWindowController.h b/Tools/MiniBrowser/mac/WK2BrowserWindowController.h
index 6f0949b0f4a..e774433031a 100644
--- a/Tools/MiniBrowser/mac/WK2BrowserWindowController.h
+++ b/Tools/MiniBrowser/mac/WK2BrowserWindowController.h
@@ -25,8 +25,11 @@
 
 #import "BrowserWindowController.h"
 
+@class WKWebView;
+
 @interface WK2BrowserWindowController : BrowserWindowController
 
 - (instancetype)initWithConfiguration:(WKWebViewConfiguration *)configuration;
+- (WKWebView *)webView;
 
 @end
diff --git a/Tools/MiniBrowser/mac/WK2BrowserWindowController.m b/Tools/MiniBrowser/mac/WK2BrowserWindowController.m
index a064395c0c4..d2da7e53df1 100644
--- a/Tools/MiniBrowser/mac/WK2BrowserWindowController.m
+++ b/Tools/MiniBrowser/mac/WK2BrowserWindowController.m
@@ -73,6 +73,7 @@ @implementation WK2BrowserWindowController {
     WKWebView *_webView;
     BOOL _zoomTextOnly;
     BOOL _isPrivateBrowsingWindow;
+    NSAlert* _alert;
 
     BOOL _useShrinkToFit;
 
@@ -83,7 +84,10 @@ @implementation WK2BrowserWindowController {
 
 - (void)awakeFromNib
 {
+    self.window.styleMask &= ~NSWindowStyleMaskFullSizeContentView;
+
     _webView = [[WKWebView alloc] initWithFrame:[containerView bounds] configuration:_configuration];
+    _webView._windowOcclusionDetectionEnabled = NO;
     [self didChangeSettings];
 
     _webView.allowsMagnification = YES;
@@ -106,7 +110,7 @@ - (void)awakeFromNib
     // telling WebKit to load every icon referenced by the page.
     if ([[SettingsController shared] loadsAllSiteIcons])
         _webView._iconLoadingDelegate = self;
-    
+
     _webView._observedRenderingProgressEvents = _WKRenderingProgressEventFirstLayout
         | _WKRenderingProgressEventFirstVisuallyNonEmptyLayout
         | _WKRenderingProgressEventFirstPaintWithSignificantArea
@@ -114,6 +118,7 @@ - (void)awakeFromNib
         | _WKRenderingProgressEventFirstPaintAfterSuppressedIncrementalRendering;
 
     _zoomTextOnly = NO;
+    _alert = nil;
 
     _webView._usePlatformFindUI = NO;
 
@@ -140,14 +145,10 @@ - (instancetype)initWithConfiguration:(WKWebViewConfiguration *)configuration
 
 - (void)dealloc
 {
-    [_webView removeObserver:self forKeyPath:@"title"];
-    [_webView removeObserver:self forKeyPath:@"URL"];
-    
     [progressIndicator unbind:NSHiddenBinding];
     [progressIndicator unbind:NSValueBinding];
 
     [_textFinder release];
-
     [_webView release];
     [_configuration release];
 
@@ -373,9 +374,15 @@ - (BOOL)windowShouldClose:(id)sender
 - (void)windowWillClose:(NSNotification *)notification
 {
     [(BrowserAppDelegate *)[[NSApplication sharedApplication] delegate] browserWindowWillClose:self.window];
+    [_webView removeObserver:self forKeyPath:@"title"];
+    [_webView removeObserver:self forKeyPath:@"URL"];
     [self autorelease];
 }
 
+- (void)webViewDidClose:(WKWebView *)webView {
+    [self.window close];
+}
+
 #define DefaultMinimumZoomFactor (.5)
 #define DefaultMaximumZoomFactor (3.0)
 #define DefaultZoomFactorRatio (1.2)
@@ -513,9 +520,11 @@ - (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSStrin
     [alert setInformativeText:message];
     [alert addButtonWithTitle:@"OK"];
 
+    _alert = alert;
     [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
         completionHandler();
         [alert release];
+        _alert = nil;
     }];
 }
 
@@ -529,9 +538,11 @@ - (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSStr
     [alert addButtonWithTitle:@"OK"];
     [alert addButtonWithTitle:@"Cancel"];
 
+    _alert = alert;
     [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
         completionHandler(response == NSAlertFirstButtonReturn);
         [alert release];
+        _alert = nil;
     }];
 }
 
@@ -549,13 +560,25 @@ - (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSSt
     [input setStringValue:defaultText];
     [alert setAccessoryView:input];
     
+    _alert = alert;
     [alert beginSheetModalForWindow:self.window completionHandler:^void (NSModalResponse response) {
         [input validateEditing];
         completionHandler(response == NSAlertFirstButtonReturn ? [input stringValue] : nil);
         [alert release];
+        _alert = nil;
     }];
 }
 
+- (void)webView:(WKWebView *)webView handleJavaScriptDialog:(BOOL)accept value:(NSString *)value
+{
+    if (!_alert)
+        return;
+    NSTextField* input = (NSTextField*)_alert.accessoryView;
+    if (accept && input && value)
+        [input setStringValue:value];
+    [self.window endSheet:_alert.window returnCode: accept ? NSAlertFirstButtonReturn : NSModalResponseCancel];
+}
+
 #if __has_feature(objc_generics)
 - (void)webView:(WKWebView *)webView runOpenPanelWithParameters:(WKOpenPanelParameters *)parameters initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSArray<NSURL *> * URLs))completionHandler
 #else
@@ -849,4 +872,9 @@ - (IBAction)saveAsWebArchive:(id)sender
     }];
 }
 
+- (WKWebView *)webView
+{
+    return _webView;
+}
+
 @end
diff --git a/Tools/MiniBrowser/wpe/main.cpp b/Tools/MiniBrowser/wpe/main.cpp
index 2d183d39412..d94d4f06fc5 100644
--- a/Tools/MiniBrowser/wpe/main.cpp
+++ b/Tools/MiniBrowser/wpe/main.cpp
@@ -172,6 +172,41 @@ static WebKitWebView* createWebView(WebKitWebView* webView, WebKitNavigationActi
     return newWebView;
 }
 
+static WebKitWebView *createNewPage(WebKitBrowserInspector*, WebKitWebContext *context)
+{
+    auto backend = createViewBackend(1280, 720);
+    struct wpe_view_backend* wpeBackend = backend->backend();
+    if (!wpeBackend)
+        return nullptr;
+
+    auto* viewBackend = webkit_web_view_backend_new(wpeBackend,
+        [](gpointer data) {
+            delete static_cast<WPEToolingBackends::ViewBackend*>(data);
+        }, backend.release());
+
+    auto* newWebView = webkit_web_view_new_with_context(viewBackend, context);
+
+    g_signal_connect(newWebView, "close", G_CALLBACK(webViewClose), nullptr);
+
+    webkit_web_view_load_uri(newWebView, "about:blank");
+
+    return newWebView;
+
+}
+
+static void closeAll(WebKitBrowserInspector*, GMainLoop* mainLoop)
+{
+    g_main_loop_quit(mainLoop);
+}
+
+static void configureBrowserInspector(GMainLoop* mainLoop, WebKitWebView *firstWebView)
+{
+    WebKitBrowserInspector* browserInspector = webkit_browser_inspector_get_default();
+    g_signal_connect(browserInspector, "create-new-page", G_CALLBACK(createNewPage), NULL);
+    // FIXME: This signal is received only when closeAll is called. We should not rely on that.
+    g_signal_connect(firstWebView, "close", G_CALLBACK(closeAll), mainLoop);
+}
+
 int main(int argc, char *argv[])
 {
 #if ENABLE_DEVELOPER_MODE
@@ -301,6 +336,8 @@ int main(int argc, char *argv[])
     g_signal_connect(webView, "permission-request", G_CALLBACK(decidePermissionRequest), nullptr);
     g_signal_connect(webView, "create", G_CALLBACK(createWebView), nullptr);
 
+    configureBrowserInspector(loop, webView);
+
     if (ignoreTLSErrors)
         webkit_web_context_set_tls_errors_policy(webContext, WEBKIT_TLS_ERRORS_POLICY_IGNORE);