Add iterator object to iterate efficiently over an Element's attributes

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 210 matching lines @@
         if (nodes.contains(n))
             sortedNodes.append(n);
 
         if (!containsAttributeNodes || !n->isElementNode())
             continue;
 
         Element* element = toElement(n);
         if (!element->hasAttributes())
             continue;
 
-        unsigned attributeCount = element->attributeCount();
-        for (unsigned i = 0; i < attributeCount; ++i) {
-            RefPtrWillBeRawPtr<Attr> attr = element->attrIfExists(element->attributeItem(i).name());
+        AttributeIteratorAccessor attributes = element->attributesIterator();
+        AttributeConstIterator end = attributes.end();
+        for (AttributeConstIterator it = attributes.begin(); it != end; ++it) {
+            RefPtrWillBeRawPtr<Attr> attr = element->attrIfExists(it->name());
             if (attr && nodes.contains(attr.get()))
                 sortedNodes.append(attr);
         }
     }
 
     ASSERT(sortedNodes.size() == nodeCount);
     const_cast<WillBeHeapVector<RefPtrWillBeMember<Node> >&>(m_nodes).swap(sortedNodes);
 }
 
 void NodeSet::reverse()
@@ skipping 22 matching lines @@
 Node* NodeSet::anyNode() const
 {
     if (isEmpty())
         return 0;
 
     return m_nodes.at(0).get();
 }
 
 }
 }