Clean up forward declarations in Source/core/html

Source/core/html/shadow/MediaControls.h

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Google 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
@@ skipping 14 matching lines @@
  */
 
 #ifndef MediaControls_h
 #define MediaControls_h
 
 #include "core/html/HTMLDivElement.h"
 #include "core/html/shadow/MediaControlElements.h"
 
 namespace blink {
 
-class Document;
 class Event;
 
 class MediaControls FINAL : public HTMLDivElement {
 public:
     static PassRefPtrWillBeRawPtr<MediaControls> create(HTMLMediaElement&);
 
     HTMLMediaElement& mediaElement() const { return *m_mediaElement; }
 
     void reset();
 
@@ skipping 91 matching lines @@
     bool m_isMouseOverControls : 1;
     bool m_isPausedForScrubbing : 1;
     bool m_wasLastEventTouch : 1;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(MediaControls, isMediaControls());
 
 }
 
 #endif