Clean forward declaration in public

public/platform/WebLayerTreeView.h

 /*
  * Copyright (C) 2011 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 20 matching lines @@
 #include "WebFloatPoint.h"
 #include "WebNonCopyable.h"
 #include "WebPrivateOwnPtr.h"
 #include "WebSize.h"
 
 class SkBitmap;
 
 namespace blink {
 
 class WebCompositeAndReadbackAsyncCallback;
-class WebGraphicsContext3D;
 class WebLayer;
 struct WebPoint;
-struct WebRect;
-struct WebRenderingStats;
 struct WebSelectionBound;
 
 class WebLayerTreeView {
 public:
     virtual ~WebLayerTreeView() { }
 
     // Initialization and lifecycle --------------------------------------
 
     // Indicates that the compositing surface used by this WebLayerTreeView is ready to use.
     // A WebLayerTreeView may request a context from its client before the surface is ready,
@@ skipping 96 matching lines @@
     // Toggles continuous painting
     virtual void setContinuousPaintingEnabled(bool) { }
 
     // Toggles scroll bottleneck rects on the HUD layer
     virtual void setShowScrollBottleneckRects(bool) { }
 };
 
 } // namespace blink
 
 #endif // WebLayerTreeView_h