Extract a DOMWindow interface from LocalDOMWindow and use it in the idl.

Source/core/events/MessageEvent.cpp

Index: Source/core/events/MessageEvent.cpp
diff --git a/Source/core/events/MessageEvent.cpp b/Source/core/events/MessageEvent.cpp
index 4879f59b9fba1c445b8a6cccaf2dd48c58dcdbb7..12ad7205e947ac976e1223c343f2ef836f18f167 100644
--- a/Source/core/events/MessageEvent.cpp
+++ b/Source/core/events/MessageEvent.cpp
@@ -135,7 +135,7 @@ PassRefPtrWillBeRawPtr<MessageEvent> MessageEvent::create(const AtomicString& ty
     return adoptRefWillBeNoop(new MessageEvent(type, initializer));
 }
 
-void MessageEvent::initMessageEvent(const AtomicString& type, bool canBubble, bool cancelable, const String& origin, const String& lastEventId, LocalDOMWindow* source, PassOwnPtrWillBeRawPtr<MessagePortArray> ports)
+void MessageEvent::initMessageEvent(const AtomicString& type, bool canBubble, bool cancelable, const String& origin, const String& lastEventId, DOMWindow* source, PassOwnPtrWillBeRawPtr<MessagePortArray> ports)
 {
     if (dispatched())
         return;
@@ -149,7 +149,7 @@ void MessageEvent::initMessageEvent(const AtomicString& type, bool canBubble, bo
     m_ports = ports;
 }
 
-void MessageEvent::initMessageEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<SerializedScriptValue> data, const String& origin, const String& lastEventId, LocalDOMWindow* source, PassOwnPtrWillBeRawPtr<MessagePortArray> ports)
+void MessageEvent::initMessageEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<SerializedScriptValue> data, const String& origin, const String& lastEventId, DOMWindow* source, PassOwnPtrWillBeRawPtr<MessagePortArray> ports)
 {
     if (dispatched())
         return;