Have ElementTraversal / NodeTraversal's next() methods take a reference

Source/core/xml/XPathUtil.cpp

 /*
  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006, 2009 Apple Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 36 matching lines @@
         case Node::COMMENT_NODE:
         case Node::TEXT_NODE:
         case Node::CDATA_SECTION_NODE:
         case Node::XPATH_NAMESPACE_NODE:
             return node->nodeValue();
         default:
             if (isRootDomNode(node) || node->nodeType() == Node::ELEMENT_NODE) {
                 StringBuilder result;
                 result.reserveCapacity(1024);
 
-                for (Node* n = node->firstChild(); n; n = NodeTraversal::next(n, node)) {
+                for (Node* n = node->firstChild(); n; n = NodeTraversal::next(*n, node)) {
                     if (n->isTextNode()) {
                         const String& nodeValue = n->nodeValue();
                         result.append(nodeValue);
                     }
                 }
 
                 return result.toString();
             }
     }
 
@@ skipping 20 matching lines @@
             return false;
         case Node::TEXT_NODE:
             return !(node->parentNode() && node->parentNode()->isAttributeNode());
     }
     ASSERT_NOT_REACHED();
     return false;
 }
 
 }
 }