Prefer to forward-declare GraphicsContext in headers.

Source/core/rendering/RenderView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 22 matching lines @@
 #include "core/rendering/FlowThreadController.h"
 #include "core/rendering/GraphicsContextAnnotator.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderSelectionInfo.h"
 #include "core/rendering/compositing/CompositedLayerMapping.h"
 #include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "core/svg/SVGDocumentExtensions.h"
+#include "platform/TraceEvent.h"
 #include "platform/geometry/FloatQuad.h"
 #include "platform/geometry/TransformState.h"
 #include "platform/graphics/GraphicsContext.h"
 
 namespace WebCore {
 
 RenderView::RenderView(Document* document)
     : RenderBlockFlow(document)
     , m_frameView(document->view())
     , m_selectionStart(0)
@@ skipping 964 matching lines @@
     return viewWidth(IncludeScrollbars) / scale;
 }
 
 double RenderView::layoutViewportHeight() const
 {
     float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 } // namespace WebCore