Remove the concept of document.documentElement

sky/engine/core/frame/LocalDOMWindow.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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
@@ skipping 73 matching lines @@
         return adoptRef(new LocalDOMWindow(frame));
     }
     virtual ~LocalDOMWindow();
 
     PassRefPtr<Document> installNewDocument(const DocumentInit&);
 
     virtual const AtomicString& interfaceName() const override;
     virtual ExecutionContext* executionContext() const override;
 
     virtual LocalDOMWindow* toDOMWindow() override;
+    void AcceptDartGCVisitor(DartGCVisitor& visitor) const override;
 
     void registerProperty(DOMWindowProperty*);
     void unregisterProperty(DOMWindowProperty*);
 
     void reset();
 
     PassRefPtr<MediaQueryList> matchMedia(const String&);
 
     unsigned pendingUnloadEventListeners() const;
 
@@ skipping 129 matching lines @@
     mutable RefPtr<Location> m_location;
 
     mutable RefPtr<DOMWindowCSS> m_css;
 
     RefPtr<DOMWindowEventQueue> m_eventQueue;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_FRAME_LOCALDOMWINDOW_H_