Have ElementData::attributeItem() return a reference

Source/core/editing/MarkupAccumulator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010 Google Inc. All rights reserved.
  *
  * 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 363 matching lines @@
     result.appendLiteral("?>");
 }
 
 void MarkupAccumulator::appendElement(StringBuilder& result, Element& element, Namespaces* namespaces)
 {
     appendOpenTag(result, element, namespaces);
 
     if (element.hasAttributes()) {
         unsigned length = element.attributeCount();
         for (unsigned int i = 0; i < length; i++)
-            appendAttribute(result, element, *element.attributeItem(i), namespaces);
+            appendAttribute(result, element, element.attributeItem(i), namespaces);
     }
 
     // Give an opportunity to subclasses to add their own attributes.
     appendCustomAttributes(result, element, namespaces);
 
     appendCloseTag(result, element);
 }
 
 static String nodeNamePreservingCase(const Element& element)
 {
@@ skipping 134 matching lines @@
 {
     if (!node.isElementNode() || shouldSelfClose(node) || (!node.hasChildren() && elementCannotHaveEndTag(node)))
         return;
 
     result.appendLiteral("</");
     result.append(nodeNamePreservingCase(toElement(node)));
     result.append('>');
 }
 
 }