Remove unused headers from RenderSVGResource.h

Source/core/rendering/svg/RenderSVGResourceContainer.h

 /*
  * Copyright (C) Research In Motion Limited 2010. 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef RenderSVGResourceContainer_h
 #define RenderSVGResourceContainer_h
 
 #include "core/rendering/svg/RenderSVGHiddenContainer.h"
 #include "core/rendering/svg/RenderSVGResource.h"
+#include "core/svg/SVGDocumentExtensions.h"
 
 namespace blink {
 
 class RenderLayer;
 
 class RenderSVGResourceContainer : public RenderSVGHiddenContainer,
                                    public RenderSVGResource {
 public:
     explicit RenderSVGResourceContainer(SVGElement*);
     virtual ~RenderSVGResourceContainer();
@@ skipping 70 matching lines @@
         return container->cast<Renderer>();
 
     return 0;
 }
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGResourceContainer, isSVGResourceContainer());
 
 }
 
 #endif