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

Source/core/xml/XPathNodeSet.cpp

 /*
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  *
  * 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 189 matching lines @@
     for (unsigned i = 0; i < nodeCount; ++i) {
         Node* node = m_nodes[i].get();
         nodes.add(node);
         if (node->isAttributeNode())
             containsAttributeNodes = true;
     }
 
     Vector<RefPtr<Node> > sortedNodes;
     sortedNodes.reserveInitialCapacity(nodeCount);
 
-    for (Node* n = findRootNode(m_nodes.first().get()); n; n = NodeTraversal::next(n)) {
+    for (Node* n = findRootNode(m_nodes.first().get()); n; n = NodeTraversal::next(*n)) {
         if (nodes.contains(n))
             sortedNodes.append(n);
 
         if (!containsAttributeNodes || !n->isElementNode())
             continue;
 
         Element* element = toElement(n);
         if (!element->hasAttributes())
             continue;
 
@@ skipping 35 matching lines @@
 Node* NodeSet::anyNode() const
 {
     if (isEmpty())
         return 0;
 
     return m_nodes.at(0).get();
 }
 
 }
 }