Have getElementsByClassName() / getElementsByTagName*() return an HTMLCollection

Source/core/dom/ContainerNode.h

 /*
  * 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, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 86 matching lines @@
     Node* childNode(unsigned index) const;
 
     PassRefPtr<Element> querySelector(const AtomicString& selectors, ExceptionState&);
     PassRefPtr<NodeList> querySelectorAll(const AtomicString& selectors, ExceptionState&);
 
     void insertBefore(PassRefPtr<Node> newChild, Node* refChild, ExceptionState& = ASSERT_NO_EXCEPTION);
     void replaceChild(PassRefPtr<Node> newChild, Node* oldChild, ExceptionState& = ASSERT_NO_EXCEPTION);
     void removeChild(Node* child, ExceptionState& = ASSERT_NO_EXCEPTION);
     void appendChild(PassRefPtr<Node> newChild, ExceptionState& = ASSERT_NO_EXCEPTION);
 
-    PassRefPtr<NodeList> getElementsByTagName(const AtomicString&);
-    PassRefPtr<NodeList> getElementsByTagNameNS(const AtomicString& namespaceURI, const AtomicString& localName);
+    PassRefPtr<HTMLCollection> getElementsByTagName(const AtomicString&);
+    PassRefPtr<HTMLCollection> getElementsByTagNameNS(const AtomicString& namespaceURI, const AtomicString& localName);
     PassRefPtr<NodeList> getElementsByName(const AtomicString& elementName);
-    PassRefPtr<NodeList> getElementsByClassName(const AtomicString& classNames);
+    PassRefPtr<HTMLCollection> getElementsByClassName(const AtomicString& classNames);
     PassRefPtr<RadioNodeList> radioNodeList(const AtomicString&, bool onlyMatchImgElements = false);
 
     // These methods are only used during parsing.
     // They don't send DOM mutation events or handle reparenting.
     // However, arbitrary code may be run by beforeload handlers.
     void parserAppendChild(PassRefPtr<Node>);
     void parserRemoveChild(Node&);
     void parserInsertBefore(PassRefPtr<Node> newChild, Node& refChild);
     void parserTakeAllChildrenFrom(ContainerNode&);
 
@@ skipping 198 matching lines @@
 
     RefPtr<Node> m_currentNode;
     unsigned m_currentIndex;
     OwnPtr<Vector<RefPtr<Node> > > m_childNodes; // Lazily instantiated.
     ChildNodesLazySnapshot* m_nextSnapshot;
 };
 
 } // namespace WebCore
 
 #endif // ContainerNode_h