Prefer to forward-declare GraphicsContext in headers.

Source/core/svg/graphics/SVGImage.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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.
@@ skipping 29 matching lines @@
 #include "core/page/Chrome.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "core/rendering/svg/RenderSVGRoot.h"
 #include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGFEImageElement.h"
 #include "core/svg/SVGImageElement.h"
 #include "core/svg/SVGSVGElement.h"
 #include "core/svg/animation/SMILTimeContainer.h"
 #include "core/svg/graphics/SVGImageChromeClient.h"
 #include "platform/LengthFunctions.h"
+#include "platform/TraceEvent.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/ImageObserver.h"
 #include "wtf/PassRefPtr.h"
 
 namespace WebCore {
 
 SVGImage::SVGImage(ImageObserver* observer)
     : Image(observer)
@@ skipping 362 matching lines @@
 
     return m_page;
 }
 
 String SVGImage::filenameExtension() const
 {
     return "svg";
 }
 
 }