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

Source/core/html/HTMLLabelElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * 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
@@ skipping 52 matching lines @@
 }
 
 LabelableElement* HTMLLabelElement::control()
 {
     const AtomicString& controlId = getAttribute(forAttr);
     if (controlId.isNull()) {
         // Search the children and descendants of the label element for a form element.
         // per http://dev.w3.org/html5/spec/Overview.html#the-label-element
         // the form element must be "labelable form-associated element".
         Element* element = this;
-        while ((element = ElementTraversal::next(element, this))) {
+        while ((element = ElementTraversal::next(*element, this))) {
             if (!supportsLabels(element))
                 continue;
             return toLabelableElement(element);
         }
         return 0;
     }
 
     if (Element* element = treeScope().getElementById(controlId)) {
         if (supportsLabels(element))
             return toLabelableElement(element);
@@ skipping 101 matching lines @@
 
 void HTMLLabelElement::accessKeyAction(bool sendMouseEvents)
 {
     if (HTMLElement* element = control())
         element->accessKeyAction(sendMouseEvents);
     else
         HTMLElement::accessKeyAction(sendMouseEvents);
 }
 
 } // namespace