Clean up forward declarations in core/rendering and core/painting

Source/core/paint/BoxPainter.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BoxPainter_h
 #define BoxPainter_h
 
 #include "core/paint/ObjectPainter.h"
 #include "core/rendering/RenderBoxModelObject.h"
 
 namespace blink {
 
+class BackgroundImageGeometry;
 class LayoutPoint;
 struct PaintInfo;
 class RenderBox;
 class RenderObject;
 
 class BoxPainter {
 public:
     BoxPainter(RenderBox& renderBox) : m_renderBox(renderBox) { }
     void paint(PaintInfo&, const LayoutPoint&);
 
@@ skipping 40 matching lines @@
         BoxSide, bool firstEdgeMatches, bool secondEdgeMatches);
     static void clipBorderSideForComplexInnerPath(GraphicsContext*, const RoundedRect&, const RoundedRect&, BoxSide, const BorderEdge[]);
 
     // FIXME: this should be const.
     RenderBox& m_renderBox;
 };
 
 } // namespace blink
 
 #endif