Share more code between local and remote postMessage

https://bugs.webkit.org/show_bug.cgi?id=254773

Reviewed by Chris Dumez.

Share the shape all the way down to the IDL.

* Source/WebCore/CMakeLists.txt:
* Source/WebCore/DerivedSources-input.xcfilelist:
* Source/WebCore/DerivedSources-output.xcfilelist:
* Source/WebCore/DerivedSources.make:
* Source/WebCore/Headers.cmake:
* Source/WebCore/Sources.txt:
* Source/WebCore/WebCore.xcodeproj/project.pbxproj:
* Source/WebCore/page/DOMWindow.cpp:
(WebCore::DOMWindow::createTargetOriginForPostMessage):
* Source/WebCore/page/DOMWindow.h:
(WebCore::DOMWindow::identifier const):
* Source/WebCore/page/DOMWindow.idl: Copied from Source/WebCore/page/DOMWindow.h.
* Source/WebCore/page/LocalDOMWindow.cpp:
(WebCore::LocalDOMWindow::postMessage):
* Source/WebCore/page/LocalDOMWindow.h:
(WebCore::WindowPostMessageOptions::WindowPostMessageOptions): Deleted.
* Source/WebCore/page/LocalDOMWindow.idl:
* Source/WebCore/page/RemoteDOMWindow.cpp:
(WebCore::RemoteDOMWindow::postMessage):
* Source/WebCore/page/RemoteDOMWindow.h:
* Source/WebCore/page/RemoteDOMWindow.idl:
* Source/WebCore/page/WindowPostMessageOptions.h: Copied from Source/WebCore/page/DOMWindow.h.
(WebCore::WindowPostMessageOptions::WindowPostMessageOptions):
* Source/WebCore/page/WindowPostMessageOptions.idl: Copied from Source/WebCore/page/DOMWindow.h.
* Tools/TestWebKitAPI/Tests/WebKitCocoa/SiteIsolation.mm:
(TestWebKitAPI::TEST):

Canonical link: https://commits.webkit.org/262437@main

Source/WebCore/CMakeLists.txt

@@ -1249,6 +1249,7 @@ set(WebCore_NON_SVG_IDL_FILES
     page/BarProp.idl
     page/Crypto.idl
     page/DOMSelection.idl
+    page/DOMWindow.idl
     page/EventSource.idl
     page/History.idl
     page/IntersectionObserver.idl
@@ -1319,6 +1320,7 @@ set(WebCore_NON_SVG_IDL_FILES
     page/WindowOrWorkerGlobalScope+Crypto.idl
     page/WindowOrWorkerGlobalScope+Performance.idl
     page/WindowOrWorkerGlobalScope.idl
+    page/WindowPostMessageOptions.idl
     page/WindowSessionStorage.idl
     page/WorkerNavigator.idl
 

Source/WebCore/DerivedSources-input.xcfilelist

@@ -1481,6 +1481,7 @@ $(PROJECT_DIR)/mathml/mathtags.in
 $(PROJECT_DIR)/page/BarProp.idl
 $(PROJECT_DIR)/page/Crypto.idl
 $(PROJECT_DIR)/page/DOMSelection.idl
+$(PROJECT_DIR)/page/DOMWindow.idl
 $(PROJECT_DIR)/page/DOMWindow+CSSOM.idl
 $(PROJECT_DIR)/page/DOMWindow+CSSOMView.idl
 $(PROJECT_DIR)/page/DOMWindow+Compat.idl
@@ -1567,6 +1568,7 @@ $(PROJECT_DIR)/page/WindowLocalStorage.idl
 $(PROJECT_DIR)/page/WindowOrWorkerGlobalScope+Crypto.idl
 $(PROJECT_DIR)/page/WindowOrWorkerGlobalScope+Performance.idl
 $(PROJECT_DIR)/page/WindowOrWorkerGlobalScope.idl
+$(PROJECT_DIR)/page/WindowPostMessageOptions.idl
 $(PROJECT_DIR)/page/WindowSessionStorage.idl
 $(PROJECT_DIR)/page/WorkerNavigator.idl
 $(PROJECT_DIR)/page/csp/CSPViolationReportBody.idl

Source/WebCore/DerivedSources-output.xcfilelist

@@ -3085,6 +3085,8 @@ $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowOrWorkerGlobalScope+Perform
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowOrWorkerGlobalScope+Performance.h
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowOrWorkerGlobalScope.cpp
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowOrWorkerGlobalScope.h
+$(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowPostMessageOptions.cpp
+$(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowPostMessageOptions.h
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowSessionStorage.cpp
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWindowSessionStorage.h
 $(BUILT_PRODUCTS_DIR)/DerivedSources/WebCore/JSWorker.cpp

Source/WebCore/DerivedSources.make

@@ -1308,6 +1308,7 @@ JS_BINDING_IDLS := \
     $(WebCore)/page/BarProp.idl \
     $(WebCore)/page/Crypto.idl \
     $(WebCore)/page/DOMSelection.idl \
+    $(WebCore)/page/DOMWindow.idl \
     $(WebCore)/page/EventSource.idl \
     $(WebCore)/page/History.idl \
     $(WebCore)/page/IntersectionObserver.idl \
@@ -1382,6 +1383,7 @@ JS_BINDING_IDLS := \
     $(WebCore)/page/WindowOrWorkerGlobalScope+Crypto.idl \
     $(WebCore)/page/WindowOrWorkerGlobalScope+Performance.idl \
     $(WebCore)/page/WindowOrWorkerGlobalScope.idl \
+    $(WebCore)/page/WindowPostMessageOptions.idl \
     $(WebCore)/page/WindowSessionStorage.idl \
     $(WebCore)/page/WorkerNavigator.idl \
     $(WebCore)/page/csp/CSPViolationReportBody.idl \

Source/WebCore/Headers.cmake

@@ -1369,6 +1369,7 @@ set(WebCore_PRIVATE_FRAMEWORK_HEADERS
     page/WheelEventTestMonitor.h
     page/WindowFeatures.h
     page/WindowOrWorkerGlobalScope.h
+    page/WindowPostMessageOptions.h
     page/WorkerClient.h
 
     page/csp/CSPViolationReportBody.h

Source/WebCore/Sources.txt

@@ -4338,6 +4338,7 @@ JSWebXRWebGLLayer.cpp
 JSWheelEvent.cpp
 JSWindowEventHandlers.cpp
 JSWindowEventHandlers+Gamepad.cpp
+JSWindowPostMessageOptions.cpp
 JSWindowOrWorkerGlobalScope.cpp
 JSWorker.cpp
 JSWorkerGlobalScope.cpp

Source/WebCore/WebCore.xcodeproj/project.pbxproj

@@ -5946,6 +5946,7 @@
 		FABE72F71059C1EB00D999DD /* MathMLPresentationElement.h in Headers */ = {isa = PBXBuildFile; fileRef = FABE72F01059C1EB00D999DD /* MathMLPresentationElement.h */; };
 		FABE72F91059C1EB00D999DD /* MathMLMathElement.h in Headers */ = {isa = PBXBuildFile; fileRef = FABE72F21059C1EB00D999DD /* MathMLMathElement.h */; };
 		FABE72FE1059C21100D999DD /* MathMLNames.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FABE72FC1059C21100D999DD /* MathMLNames.cpp */; };
+		FAEF5F6129D62710000AD8EC /* WindowPostMessageOptions.h in Headers */ = {isa = PBXBuildFile; fileRef = FAEF5F5F29D6241C000AD8EC /* WindowPostMessageOptions.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		FB273E822086E6C700A54E87 /* SVGGeometryElement.h in Headers */ = {isa = PBXBuildFile; fileRef = FB273E7F2086E6A300A54E87 /* SVGGeometryElement.h */; };
 		FB273E852086E74D00A54E87 /* JSSVGGeometryElement.h in Headers */ = {isa = PBXBuildFile; fileRef = FB273E842086E73E00A54E87 /* JSSVGGeometryElement.h */; };
 		FB2C15C3165D649D0039C9F8 /* CachedSVGDocumentReference.h in Headers */ = {isa = PBXBuildFile; fileRef = FB2C15C2165D64900039C9F8 /* CachedSVGDocumentReference.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -19147,6 +19148,9 @@
 		FABE72F31059C1EB00D999DD /* mathtags.in */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = mathtags.in; sourceTree = "<group>"; };
 		FABE72FB1059C21100D999DD /* MathMLElementFactory.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = MathMLElementFactory.cpp; sourceTree = "<group>"; };
 		FABE72FC1059C21100D999DD /* MathMLNames.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = MathMLNames.cpp; sourceTree = "<group>"; };
+		FAEF5F5F29D6241C000AD8EC /* WindowPostMessageOptions.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = WindowPostMessageOptions.h; sourceTree = "<group>"; };
+		FAEF5F6029D626D1000AD8EC /* WindowPostMessageOptions.idl */ = {isa = PBXFileReference; lastKnownFileType = text; path = WindowPostMessageOptions.idl; sourceTree = "<group>"; };
+		FAEF5F6229D62D15000AD8EC /* DOMWindow.idl */ = {isa = PBXFileReference; lastKnownFileType = text; path = DOMWindow.idl; sourceTree = "<group>"; };
 		FB273E7E2086E6A300A54E87 /* SVGGeometryElement.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = SVGGeometryElement.cpp; sourceTree = "<group>"; };
 		FB273E7F2086E6A300A54E87 /* SVGGeometryElement.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = SVGGeometryElement.h; sourceTree = "<group>"; };
 		FB273E802086E6A300A54E87 /* SVGGeometryElement.idl */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = SVGGeometryElement.idl; sourceTree = "<group>"; };
@@ -25663,6 +25667,7 @@
 				188604B20F2E654A000B6443 /* DOMTimer.h */,
 				46B95193207D632F00A7D2DD /* DOMWindow.cpp */,
 				46B9518A207D632800A7D2DD /* DOMWindow.h */,
+				FAEF5F6229D62D15000AD8EC /* DOMWindow.idl */,
 				517FBA17151AA71B00B57959 /* DOMWindowExtension.cpp */,
 				517FBA18151AA71B00B57959 /* DOMWindowExtension.h */,
 				A718760D0B2A120100A16ECE /* DragActions.h */,
@@ -25994,6 +25999,8 @@
 				460C745626DD699D00427D3E /* WindowOrWorkerGlobalScope.cpp */,
 				460C745826DD699D00427D3E /* WindowOrWorkerGlobalScope.h */,
 				9371080D1DB754550060744E /* WindowOrWorkerGlobalScope.idl */,
+				FAEF5F5F29D6241C000AD8EC /* WindowPostMessageOptions.h */,
+				FAEF5F6029D626D1000AD8EC /* WindowPostMessageOptions.idl */,
 				7C67712C2527D7C900FDEF00 /* WindowSessionStorage.idl */,
 				A7A3D55028939156008D683D /* WorkerClient.h */,
 				E1271A130EEEC80400F61213 /* WorkerNavigator.cpp */,
@@ -40587,6 +40594,7 @@
 				460C745926DD69BB00427D3E /* WindowOrWorkerGlobalScope.h in Headers */,
 				41D129CE1F3D0EF600D15E47 /* WindowOrWorkerGlobalScopeCaches.h in Headers */,
 				5185FCB41BB4C4E80012898F /* WindowOrWorkerGlobalScopeIndexedDatabase.h in Headers */,
+				FAEF5F6129D62710000AD8EC /* WindowPostMessageOptions.h in Headers */,
 				463521AD2081092A00C28922 /* WindowProxy.h in Headers */,
 				E1E1BF00115FF6FB006F52CA /* WindowsKeyboardCodes.h in Headers */,
 				501BAAA913950E2C00F7ACEB /* WindRule.h in Headers */,

Source/WebCore/page/DOMWindow.cpp

@@ -54,21 +54,18 @@ DOMWindow::~DOMWindow()
     allWindows().remove(identifier());
 }
 
-std::optional<ExceptionOr<RefPtr<SecurityOrigin>>> DOMWindow::createTargetOriginForPostMessage(const String& targetOrigin, RefPtr<Document>& sourceDocument)
+ExceptionOr<RefPtr<SecurityOrigin>> DOMWindow::createTargetOriginForPostMessage(const String& targetOrigin, Document& sourceDocument)
 {
     RefPtr<SecurityOrigin> targetSecurityOrigin;
-    if (targetOrigin == "/"_s) {
-        if (!sourceDocument)
-            return std::nullopt;
-        targetSecurityOrigin = &sourceDocument->securityOrigin();
-    } else if (targetOrigin != "*"_s) {
+    if (targetOrigin == "/"_s)
+        targetSecurityOrigin = &sourceDocument.securityOrigin();
+    else if (targetOrigin != "*"_s) {
         targetSecurityOrigin = &SecurityOrigin::createFromString(targetOrigin).leakRef();
         // It doesn't make sense target a postMessage at an opaque origin
         // because there's no way to represent an opaque origin in a string.
         if (targetSecurityOrigin->isOpaque())
             return Exception { SyntaxError };
     }
-
     return targetSecurityOrigin;
 }
 

Source/WebCore/page/DOMWindow.h

@@ -44,7 +44,6 @@ class DOMWindow : public RefCounted<DOMWindow>, public EventTarget {
     static HashMap<GlobalWindowIdentifier, DOMWindow*>& allWindows();
 
     const GlobalWindowIdentifier& identifier() const { return m_identifier; }
-    std::optional<ExceptionOr<RefPtr<SecurityOrigin>>> createTargetOriginForPostMessage(const String&, RefPtr<Document>&);
     virtual Frame* frame() const = 0;
 
     virtual bool isLocalDOMWindow() const = 0;
@@ -56,6 +55,8 @@ class DOMWindow : public RefCounted<DOMWindow>, public EventTarget {
 protected:
     explicit DOMWindow(GlobalWindowIdentifier&&);
 
+    ExceptionOr<RefPtr<SecurityOrigin>> createTargetOriginForPostMessage(const String&, Document&);
+
     EventTargetInterface eventTargetInterface() const final { return LocalDOMWindowEventTargetInterfaceType; }
     void refEventTarget() final { ref(); }
     void derefEventTarget() final { deref(); }

Source/WebCore/page/DOMWindow.idl

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2023 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+interface mixin DOMWindow {
+    [CallWith=CurrentGlobalObject&IncumbentWindow, DoNotCheckSecurity] undefined postMessage(any message, USVString targetOrigin, optional sequence<object> transfer = []);
+    [CallWith=CurrentGlobalObject&IncumbentWindow, DoNotCheckSecurity] undefined postMessage(any message, optional WindowPostMessageOptions options);
+};

Source/WebCore/page/LocalDOMWindow.cpp

@@ -954,18 +954,9 @@ ExceptionOr<void> LocalDOMWindow::postMessage(JSC::JSGlobalObject& lexicalGlobal
     if (!sourceDocument)
         return { };
 
-    // Compute the target origin. We need to do this synchronously in order
-    // to generate the SyntaxError exception correctly.
-    std::optional<ExceptionOr<RefPtr<SecurityOrigin>>> targetSecurityOrigin = createTargetOriginForPostMessage(options.targetOrigin, sourceDocument);
-    if (!targetSecurityOrigin)
-        return { };
-
-    if (targetSecurityOrigin->hasException())
-        return targetSecurityOrigin->releaseException();
-
-    RefPtr<SecurityOrigin> target;
-    if (targetSecurityOrigin->returnValue())
-        target = targetSecurityOrigin->releaseReturnValue();
+    auto targetSecurityOrigin = createTargetOriginForPostMessage(options.targetOrigin, *sourceDocument);
+    if (targetSecurityOrigin.hasException())
+        return targetSecurityOrigin.releaseException();
 
     Vector<RefPtr<MessagePort>> ports;
     auto messageData = SerializedScriptValue::create(lexicalGlobalObject, messageValue, WTFMove(options.transfer), ports, SerializationForStorage::No, SerializationContext::WindowPostMessage);
@@ -979,7 +970,7 @@ ExceptionOr<void> LocalDOMWindow::postMessage(JSC::JSGlobalObject& lexicalGlobal
     // Schedule the message.
     RefPtr<WindowProxy> incumbentWindowProxy = incumbentWindow.frame() ? &incumbentWindow.frame()->windowProxy() : nullptr;
     MessageWithMessagePorts message { messageData.releaseReturnValue(), disentangledPorts.releaseReturnValue() };
-    processPostMessage(lexicalGlobalObject, WTFMove(sourceDocument), message, WTFMove(incumbentWindowProxy), WTFMove(target));
+    processPostMessage(lexicalGlobalObject, WTFMove(sourceDocument), message, WTFMove(incumbentWindowProxy), targetSecurityOrigin.releaseReturnValue());
     return { };
 }
 

Source/WebCore/page/LocalDOMWindow.h

@@ -35,9 +35,9 @@
 #include "ReducedResolutionSeconds.h"
 #include "ScrollToOptions.h"
 #include "ScrollTypes.h"
-#include "StructuredSerializeOptions.h"
 #include "Supplementable.h"
 #include "WindowOrWorkerGlobalScope.h"
+#include "WindowPostMessageOptions.h"
 #include <JavaScriptCore/HandleTypes.h>
 #include <JavaScriptCore/Strong.h>
 #include <wtf/FixedVector.h>
@@ -102,16 +102,6 @@ struct WindowFeatures;
 enum SetLocationLocking { LockHistoryBasedOnGestureState, LockHistoryAndBackForwardList };
 enum class IncludeTargetOrigin : bool { No, Yes };
 
-struct WindowPostMessageOptions : public StructuredSerializeOptions {
-    WindowPostMessageOptions() = default;
-    WindowPostMessageOptions(String&& targetOrigin, Vector<JSC::Strong<JSC::JSObject>>&& transfer)
-        : StructuredSerializeOptions(WTFMove(transfer))
-        , targetOrigin(WTFMove(targetOrigin))
-    { }
-
-    String targetOrigin { "/"_s };
-};
-
 class LocalDOMWindow final
     : public DOMWindow
     , public ContextDestructionObserver

Source/WebCore/page/LocalDOMWindow.idl

@@ -87,10 +87,6 @@
     DOMString? prompt(optional DOMString message = "", optional DOMString defaultValue = "");
     undefined print();
 
-    [CallWith=CurrentGlobalObject&IncumbentWindow, DoNotCheckSecurity] undefined postMessage(any message, USVString targetOrigin, optional sequence<object> transfer = []);
-    [CallWith=CurrentGlobalObject&IncumbentWindow, DoNotCheckSecurity] undefined postMessage(any message, optional WindowPostMessageOptions options);
-
-
     // Obsolete: Still part of the HTML specification (https://html.spec.whatwg.org/#Window-partial).
     undefined captureEvents();
     undefined releaseEvents();
@@ -126,14 +122,9 @@
     [EnabledForWorld=shadowRootIsAlwaysOpen] Element? matchingElementInFlatTree(Node scope, DOMString selectors);
 };
 
-[
-    ImplementedAs=WindowPostMessageOptions
-] dictionary WindowPostMessageOptions : StructuredSerializeOptions {
-    USVString targetOrigin = "/";
-};
-
 LocalDOMWindow includes AnimationFrameProvider;
 LocalDOMWindow includes GlobalEventHandlers;
+LocalDOMWindow includes DOMWindow;
 LocalDOMWindow includes WindowEventHandlers;
 LocalDOMWindow includes WindowOrWorkerGlobalScope;
 LocalDOMWindow includes WindowLocalStorage;

Source/WebCore/page/RemoteDOMWindow.cpp

@@ -114,23 +114,22 @@ WindowProxy* RemoteDOMWindow::parent() const
     return &m_frame->windowProxy();
 }
 
-ExceptionOr<void> RemoteDOMWindow::postMessage(JSC::JSGlobalObject& lexicalGlobalObject, LocalDOMWindow& incumbentWindow, JSC::JSValue message, const String& targetOrigin, Vector<JSC::Strong<JSC::JSObject>>&& transfer)
+ExceptionOr<void> RemoteDOMWindow::postMessage(JSC::JSGlobalObject& lexicalGlobalObject, LocalDOMWindow& incumbentWindow, JSC::JSValue message, WindowPostMessageOptions&& options)
 {
     RefPtr sourceDocument = incumbentWindow.document();
-    // Compute the target origin. We need to do this synchronously in order
-    // to generate the SyntaxError exception correctly.
-    std::optional<ExceptionOr<RefPtr<SecurityOrigin>>> targetSecurityOrigin = createTargetOriginForPostMessage(targetOrigin, sourceDocument);
-    if (!targetSecurityOrigin)
+    if (!sourceDocument)
         return { };
-    if (targetSecurityOrigin->hasException())
-        return targetSecurityOrigin->releaseException();
+
+    auto targetSecurityOrigin = createTargetOriginForPostMessage(options.targetOrigin, *sourceDocument);
+    if (targetSecurityOrigin.hasException())
+        return targetSecurityOrigin.releaseException();
 
     std::optional<SecurityOriginData> target;
-    if (targetSecurityOrigin->returnValue())
-        target = targetSecurityOrigin->releaseReturnValue()->data();
+    if (auto origin = targetSecurityOrigin.releaseReturnValue())
+        target = origin->data();
 
     Vector<RefPtr<MessagePort>> ports;
-    auto messageData = SerializedScriptValue::create(lexicalGlobalObject, message, WTFMove(transfer), ports, SerializationForStorage::No, SerializationContext::WindowPostMessage);
+    auto messageData = SerializedScriptValue::create(lexicalGlobalObject, message, WTFMove(options.transfer), ports, SerializationForStorage::No, SerializationContext::WindowPostMessage);
     if (messageData.hasException())
         return messageData.releaseException();
 

Source/WebCore/page/RemoteDOMWindow.h

@@ -27,6 +27,7 @@
 
 #include "DOMWindow.h"
 #include "RemoteFrame.h"
+#include "WindowPostMessageOptions.h"
 #include <JavaScriptCore/Strong.h>
 #include <wtf/IsoMalloc.h>
 #include <wtf/TypeCasts.h>
@@ -68,7 +69,11 @@ class RemoteDOMWindow final : public DOMWindow {
     WindowProxy* top() const;
     WindowProxy* opener() const;
     WindowProxy* parent() const;
-    ExceptionOr<void> postMessage(JSC::JSGlobalObject&, LocalDOMWindow& incumbentWindow, JSC::JSValue message, const String& targetOrigin, Vector<JSC::Strong<JSC::JSObject>>&&);
+    ExceptionOr<void> postMessage(JSC::JSGlobalObject&, LocalDOMWindow& incumbentWindow, JSC::JSValue message, WindowPostMessageOptions&&);
+    ExceptionOr<void> postMessage(JSC::JSGlobalObject& globalObject, LocalDOMWindow& incumbentWindow, JSC::JSValue message, String&& targetOrigin, Vector<JSC::Strong<JSC::JSObject>>&& transfer)
+    {
+        return postMessage(globalObject, incumbentWindow, message, WindowPostMessageOptions { WTFMove(targetOrigin), WTFMove(transfer) });
+    }
 
 private:
     WEBCORE_EXPORT RemoteDOMWindow(RemoteFrame&, GlobalWindowIdentifier&&);

Source/WebCore/page/RemoteDOMWindow.idl

@@ -53,5 +53,6 @@
     [LegacyUnforgeable] readonly attribute WindowProxy? top;
     readonly attribute WindowProxy? opener;
     [Replaceable] readonly attribute WindowProxy? parent;
-    [CallWith=CurrentGlobalObject&IncumbentWindow] undefined postMessage(any message, USVString targetOrigin, optional sequence<object> transfer = []);
 };
+
+RemoteDOMWindow includes DOMWindow;