WebMessaging: Show a warning when MessagePort attempts to send a transferable ArrayBuffer

In the current implementation, MessagePort does not support sending an
ArrayBuffer as a transferable object yet and unexpectedly loses the buffer
without any warning.

BUG=334408

Review URL: https://codereview.chromium.org/1301953002

git-svn-id: svn://svn.chromium.org/blink/trunk@200832 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/fast/events/message-port-clone-expected.txt

+CONSOLE WARNING: MessagePort cannot send an ArrayBuffer as a transferable object yet. See http://crbug.com/334408
+CONSOLE WARNING: MessagePort cannot send an ArrayBuffer as a transferable object yet. See http://crbug.com/334408
 Tests various use cases when cloning MessagePorts.
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp

@@ -238,6 +238,11 @@ void SerializedScriptValue::registerMemoryAllocatedWithCurrentScriptContext()
     v8::Isolate::GetCurrent()->AdjustAmountOfExternalAllocatedMemory(m_externallyAllocatedMemory);
 }
 
+bool SerializedScriptValue::containsTransferableArrayBuffer() const
+{
+    return m_arrayBufferContentsArray && !m_arrayBufferContentsArray->isEmpty();
+}
+
 SerializedScriptValue::~SerializedScriptValue()
 {
     // If the allocated memory was not registered before, then this class is likely

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.h

@@ -97,6 +97,9 @@ public:
     // The memory registration is revoked automatically in destructor.
     void registerMemoryAllocatedWithCurrentScriptContext();
 
+    // Returns true if the value contains a transferable ArrayBuffer.
+    bool containsTransferableArrayBuffer() const;
+
 private:
     // The followings are private, but used by SerializedScriptValueFactory.
     enum StringDataMode {

third_party/WebKit/Source/core/dom/MessagePort.cpp

@@ -36,6 +36,7 @@
 #include "core/dom/ExecutionContext.h"
 #include "core/events/MessageEvent.h"
 #include "core/frame/LocalDOMWindow.h"
+#include "core/inspector/ConsoleMessage.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "public/platform/WebString.h"
 #include "wtf/Functional.h"
@@ -87,6 +88,9 @@ void MessagePort::postMessage(ExecutionContext* context, PassRefPtr<SerializedSc
             return;
     }
 
+    if (message->containsTransferableArrayBuffer())
+        executionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel, "MessagePort cannot send an ArrayBuffer as a transferable object yet. See http://crbug.com/334408"));
+
     WebString messageString = message->toWireString();
     OwnPtr<WebMessagePortChannelArray> webChannels = toWebMessagePortChannelArray(channels.release());
     m_entangledChannel->postMessage(messageString, webChannels.leakPtr());