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

Source/core/dom/MessagePort.cpp

Index: Source/core/dom/MessagePort.cpp
diff --git a/Source/core/dom/MessagePort.cpp b/Source/core/dom/MessagePort.cpp
index d9da4a2e26a76e97ed76ca6076dc57a389cf9513..4138eefee0ca69bdf033897ed8e87e7c582cf264 100644
--- a/Source/core/dom/MessagePort.cpp
+++ b/Source/core/dom/MessagePort.cpp
@@ -266,4 +266,16 @@ void MessagePort::trace(Visitor* visitor)
     EventTargetWithInlineData::trace(visitor);
 }
 
+v8::Isolate* MessagePort::scriptIsolate()
+{
+    ASSERT(executionContext());
+    return toIsolate(executionContext());
+}
+
+v8::Handle<v8::Context> MessagePort::scriptContext()
+{
+    ASSERT(executionContext());
+    return toV8Context(executionContext(), DOMWrapperWorld::mainWorld());
+}
+
 } // namespace blink