Clean up forward declarations in Source/core/page

Source/core/page/scrolling/ScrollingCoordinator.h

 /*
  * Copyright (C) 2011 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 15 matching lines @@
 #ifndef ScrollingCoordinator_h
 #define ScrollingCoordinator_h
 
 #include "core/rendering/RenderObject.h"
 #include "platform/PlatformWheelEvent.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
-class WebLayer;
 class WebScrollbarLayer;
 }
 
 namespace blink {
 
 typedef unsigned MainThreadScrollingReasons;
 
-class Document;
 class LocalFrame;
 class FrameView;
 class GraphicsLayer;
 class Page;
 class Region;
 class ScrollableArea;
-class ViewportConstraints;
 
 class ScrollingCoordinator {
 public:
     ~ScrollingCoordinator();
 
     static PassOwnPtr<ScrollingCoordinator> create(Page*);
 
     void willBeDestroyed();
 
     // Return whether this scrolling coordinator handles scrolling for the given frame view.
@@ skipping 89 matching lines @@
     HashSet<const RenderLayer*> m_layersWithTouchRects;
     bool m_wasFrameScrollable;
 
     // This is retained for testing.
     MainThreadScrollingReasons m_lastMainThreadScrollingReasons;
 };
 
 } // namespace blink
 
 #endif // ScrollingCoordinator_h