Expose v8 context a MessagePort lives in to give content side code a valid context to (de)serialize…

Source/core/dom/MessagePort.cpp

 /*
  * Copyright (C) 2008 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
@@ skipping 43 matching lines @@
     : ActiveDOMObject(&executionContext)
     , m_started(false)
     , m_closed(false)
     , m_weakFactory(this)
 {
 }
 
 MessagePort::~MessagePort()
 {
     close();
+    if (m_scriptStateForConversion)
+        m_scriptStateForConversion->disposePerContextData();
 }
 
 void MessagePort::postMessage(ExecutionContext*, PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
 {
     if (!isEntangled())
         return;
     ASSERT(executionContext());
     ASSERT(m_entangledChannel);
 
     OwnPtr<MessagePortChannelArray> channels;
@@ skipping 185 matching lines @@
     }
     return portArray.release();
 }
 
 DEFINE_TRACE(MessagePort)
 {
     ActiveDOMObject::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
 }
 
+v8::Isolate* MessagePort::scriptIsolate()
+{
+    ASSERT(executionContext());
+    return toIsolate(executionContext());
+}
+
+v8::Local<v8::Context> MessagePort::scriptContextForMessageConversion()
+{
+    ASSERT(executionContext());
+    if (!m_scriptStateForConversion) {
+        v8::Isolate* isolate = scriptIsolate();
+        m_scriptStateForConversion = ScriptState::create(v8::Context::New(isolate), DOMWrapperWorld::create(isolate));
+    }
+    return m_scriptStateForConversion->context();
+}
+
 } // namespace blink