Have SVGURIReference API deal with Document references, not pointers

Source/core/svg/SVGURIReference.h

 /*
  * Copyright (C) 2004, 2005, 2008, 2009 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  *
  * 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 18 matching lines @@
 class Element;
 
 class SVGURIReference {
 public:
     virtual ~SVGURIReference() { }
 
     bool parseAttribute(const QualifiedName&, const AtomicString&);
     bool isKnownAttribute(const QualifiedName&);
     void addSupportedAttributes(HashSet<QualifiedName>&);
 
-    static String fragmentIdentifierFromIRIString(const String&, Document*);
-    static Element* targetElementFromIRIString(const String&, Document*, String* = 0, Document* = 0);
+    static String fragmentIdentifierFromIRIString(const String&, const Document&);
+    static Element* targetElementFromIRIString(const String&, const Document&, String* = 0, Document* = 0);
 
-    static inline bool isExternalURIReference(const String& uri, Document* document)
+    static inline bool isExternalURIReference(const String& uri, const Document& document)
     {
         // Fragment-only URIs are always internal
         if (uri.startsWith('#'))
             return false;
 
         // If the URI matches our documents URL, we're dealing with a local reference.
-        ASSERT(document);
-        KURL url = document->completeURL(uri);
-        return !equalIgnoringFragmentIdentifier(url, document->url());
+        KURL url = document.completeURL(uri);
+        return !equalIgnoringFragmentIdentifier(url, document.url());
     }
 
 protected:
     virtual void setHrefBaseValue(const String&, const bool validValue = true) = 0;
 };
 
 } // namespace WebCore
 
 #endif // SVGURIReference_h