Have ElementData::attributeItem() return a reference

Source/core/dom/DatasetDOMStringMap.cpp

 /*
  * Copyright (C) 2010 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 139 matching lines @@
     m_element->deref();
 }
 
 void DatasetDOMStringMap::getNames(Vector<String>& names)
 {
     if (!m_element->hasAttributes())
         return;
 
     unsigned length = m_element->attributeCount();
     for (unsigned i = 0; i < length; i++) {
-        const Attribute* attribute = m_element->attributeItem(i);
-        if (isValidAttributeName(attribute->localName()))
-            names.append(convertAttributeNameToPropertyName(attribute->localName()));
+        const Attribute& attribute = m_element->attributeItem(i);
+        if (isValidAttributeName(attribute.localName()))
+            names.append(convertAttributeNameToPropertyName(attribute.localName()));
     }
 }
 
 String DatasetDOMStringMap::item(const String& name)
 {
     if (!m_element->hasAttributes())
         return String();
 
     unsigned length = m_element->attributeCount();
     for (unsigned i = 0; i < length; i++) {
-        const Attribute* attribute = m_element->attributeItem(i);
-        if (propertyNameMatchesAttributeName(name, attribute->localName()))
-            return attribute->value();
+        const Attribute& attribute = m_element->attributeItem(i);
+        if (propertyNameMatchesAttributeName(name, attribute.localName()))
+            return attribute.value();
     }
 
     return String();
 }
 
 bool DatasetDOMStringMap::contains(const String& name)
 {
     if (!m_element->hasAttributes())
         return false;
 
     unsigned length = m_element->attributeCount();
     for (unsigned i = 0; i < length; i++) {
-        const Attribute* attribute = m_element->attributeItem(i);
-        if (propertyNameMatchesAttributeName(name, attribute->localName()))
+        const Attribute& attribute = m_element->attributeItem(i);
+        if (propertyNameMatchesAttributeName(name, attribute.localName()))
             return true;
     }
 
     return false;
 }
 
 void DatasetDOMStringMap::setItem(const String& name, const String& value, ExceptionState& exceptionState)
 {
     if (!isValidPropertyName(name)) {
         exceptionState.throwDOMException(SyntaxError, "'" + name + "' is not a valid property name.");
         return;
     }
 
     m_element->setAttribute(convertPropertyNameToAttributeName(name), AtomicString(value), exceptionState);
 }
 
 bool DatasetDOMStringMap::deleteItem(const String& name)
 {
     if (isValidPropertyName(name)) {
         AtomicString attributeName = convertPropertyNameToAttributeName(name);
         if (m_element->hasAttribute(attributeName)) {
             m_element->removeAttribute(attributeName);
             return true;
         }
     }
     return false;
 }
 
 } // namespace WebCore