This CL clean up patch in SVGElements.

Source/core/svg/SVGURIReference.cpp

 /*
  * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 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 66 matching lines @@
 }
 
 Element* SVGURIReference::targetElementFromIRIString(const String& iri, const TreeScope& treeScope, AtomicString* fragmentIdentifier, Document* externalDocument)
 {
     const Document& document = treeScope.document();
 
     // If there's no fragment identifier contained within the IRI string, we can't lookup an element.
     AtomicString id;
     KURL url = urlFromIRIStringWithFragmentIdentifier(iri, document, id);
     if (url == KURL())
-        return 0;
+        return nullptr;
 
     if (fragmentIdentifier)
         *fragmentIdentifier = id;
 
     if (id.isEmpty())
-        return 0;
+        return nullptr;
 
     if (externalDocument) {
         // Enforce that the referenced url matches the url of the document that we've loaded for it!
         ASSERT(equalIgnoringFragmentIdentifier(url, externalDocument->url()));
         return externalDocument->getElementById(id);
     }
 
     // Exit early if the referenced url is external, and we have no externalDocument given.
     if (isExternalURIReference(iri, document))
-        return 0;
+        return nullptr;
 
     return treeScope.getElementById(id);
 }
 
 void SVGURIReference::addSupportedAttributes(HashSet<QualifiedName>& supportedAttributes)
 {
     supportedAttributes.add(XLinkNames::hrefAttr);
 }
 
 }