Reduce forward declarations in core/rendering

Source/core/rendering/compositing/RenderLayerCompositor.h

 /*
  * Copyright (C) 2009 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 16 matching lines @@
 #define RenderLayerCompositor_h
 
 #include "core/page/ChromeClient.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/compositing/CompositingReasonFinder.h"
 #include "platform/graphics/GraphicsLayerClient.h"
 #include "wtf/HashMap.h"
 
 namespace WebCore {
 
-class FixedPositionViewportConstraints;
 class GraphicsLayer;
-class RenderEmbeddedObject;
-class RenderLayerStackingNode;
 class RenderPart;
-class RenderVideo;
 class ScrollingCoordinator;
-class StickyPositionViewportConstraints;
 
 enum CompositingUpdateType {
     CompositingUpdateNone,
     CompositingUpdateAfterGeometryChange,
     CompositingUpdateAfterCompositingInputChange,
     CompositingUpdateRebuildTree,
 };
 
 enum CompositingStateTransitionType {
     NoCompositingStateChange,
@@ skipping 221 matching lines @@
 #if USE(RUBBER_BANDING)
     OwnPtr<GraphicsLayer> m_layerForOverhangShadow;
 #endif
 
     bool m_inOverlayFullscreenVideo;
 };
 
 } // namespace WebCore
 
 #endif // RenderLayerCompositor_h