Have SVGURIReference API deal with Document references, not pointers

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
@@ skipping 57 matching lines @@
     virtual void willBeDestroyed() OVERRIDE FINAL;
     void registerResource();
 
     AtomicString m_id;
     bool m_registered : 1;
     bool m_isInvalidating : 1;
     HashSet<RenderObject*> m_clients;
     HashSet<RenderLayer*> m_clientLayers;
 };
 
-inline RenderSVGResourceContainer* getRenderSVGResourceContainerById(Document* document, const AtomicString& id)
+inline RenderSVGResourceContainer* getRenderSVGResourceContainerById(Document& document, const AtomicString& id)
 {
     if (id.isEmpty())
         return 0;
 
-    if (RenderSVGResourceContainer* renderResource = document->accessSVGExtensions()->resourceById(id))
+    if (RenderSVGResourceContainer* renderResource = document.accessSVGExtensions()->resourceById(id))
         return renderResource;
 
     return 0;
 }
 
 template<typename Renderer>
-Renderer* getRenderSVGResourceById(Document* document, const AtomicString& id)
+Renderer* getRenderSVGResourceById(Document& document, const AtomicString& id)
 {
     if (RenderSVGResourceContainer* container = getRenderSVGResourceContainerById(document, id))
         return container->cast<Renderer>();
 
     return 0;
 }
 
 }
 
 #endif