Prefer to forward-declare GraphicsContext in headers.

Source/core/page/ChromeClient.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple, Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 16 matching lines @@
 #include "core/loader/FrameLoader.h"
 #include "core/loader/NavigationPolicy.h"
 #include "core/frame/ConsoleTypes.h"
 #include "core/page/FocusType.h"
 #include "core/rendering/RenderEmbeddedObject.h"
 #include "core/rendering/style/RenderStyleConstants.h"
 #include "platform/Cursor.h"
 #include "platform/HostWindow.h"
 #include "platform/PopupMenu.h"
 #include "platform/PopupMenuClient.h"
-#include "platform/graphics/GraphicsContext.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "wtf/Forward.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/Vector.h"
 
 
 #ifndef __OBJC__
 class NSMenu;
 class NSResponder;
 #endif
 
 namespace WebCore {
 
 class AXObject;
 class ColorChooser;
 class ColorChooserClient;
 class DateTimeChooser;
 class DateTimeChooserClient;
 class Element;
 class FileChooser;
 class FloatRect;
 class Frame;
+class GraphicsContext;
 class GraphicsLayer;
 class GraphicsLayerFactory;
 class HitTestResult;
 class HTMLFormControlElement;
 class HTMLInputElement;
 class IntRect;
 class LocalFrame;
 class Node;
 class Page;
 class PagePopup;
@@ skipping 167 matching lines @@
     virtual void didCancelCompositionOnSelectionChange() { }
     virtual void willSetInputMethodState() { }
     virtual void didUpdateTextOfFocusedElementByNonUserInput() { }
 
 protected:
     virtual ~ChromeClient() { }
 };
 
 }
 #endif // ChromeClient_h