Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/OverscrollTheme.h

 /*
  * Copyright (C) 2013 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
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY GOOGLE, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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 #ifndef OverscrollTheme_h
 #define OverscrollTheme_h
 
-#include "core/platform/graphics/GraphicsLayer.h"
-#include "core/platform/graphics/Image.h"
+#include "platform/graphics/GraphicsLayer.h"
+#include "platform/graphics/Image.h"
 
 namespace WebCore {
 
 class OverscrollTheme {
     WTF_MAKE_NONCOPYABLE(OverscrollTheme); WTF_MAKE_FAST_ALLOCATED;
 public:
     OverscrollTheme();
     virtual ~OverscrollTheme() { }
 
     virtual PassRefPtr<Image> getOverhangImage();
     virtual void setUpOverhangShadowLayer(GraphicsLayer*);
     virtual void updateOverhangShadowLayer(GraphicsLayer* shadowLayer, GraphicsLayer* rootContentLayer);
 
     static OverscrollTheme* theme();
 
 private:
     RefPtr<Image> m_overhangShadow;
     RefPtr<Image> m_overhangPattern;
 };
 
 }
 
 #endif