Prefer to forward-declare GraphicsContext in headers.

Source/core/rendering/compositing/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 32 matching lines @@
 #include "core/rendering/RenderLayerStackingNode.h"
 #include "core/rendering/RenderLayerStackingNodeIterator.h"
 #include "core/rendering/RenderVideo.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/compositing/CompositedLayerMapping.h"
 #include "core/rendering/compositing/CompositingLayerAssigner.h"
 #include "core/rendering/compositing/CompositingRequirementsUpdater.h"
 #include "core/rendering/compositing/GraphicsLayerTreeBuilder.h"
 #include "core/rendering/compositing/GraphicsLayerUpdater.h"
 #include "platform/OverscrollTheme.h"
+#include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "public/platform/Platform.h"
 
 namespace WebCore {
 
 class DeprecatedDirtyCompositingDuringCompositingUpdate {
     WTF_MAKE_NONCOPYABLE(DeprecatedDirtyCompositingDuringCompositingUpdate);
 public:
     DeprecatedDirtyCompositingDuringCompositingUpdate(DocumentLifecycle& lifecycle)
         : m_lifecycle(lifecycle)
@@ skipping 1246 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore