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

Source/core/html/CollectionType.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 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 34 matching lines @@
     TableTBodies, // all <tbody> elements in this table
     TSectionRows, // all row elements in this table section
     TableRows,
     TRCells,      // all cells in this row
     SelectOptions,
     SelectedOptions,
     DataListOptions,
     MapAreas,
     FormControls,
 
+    ClassCollectionType,
+    TagCollectionType,
+    HTMLTagCollectionType,
+
     // Live NodeList.
     ChildNodeListType,
-    ClassNodeListType,
     NameNodeListType,
-    TagNodeListType,
-    HTMLTagNodeListType,
     RadioNodeListType,
     RadioImgNodeListType,
     LabelsNodeListType,
 };
 
 static const CollectionType FirstLiveNodeListType = ChildNodeListType;
 
 inline bool isLiveNodeListType(CollectionType type)
 {
     return type >= FirstLiveNodeListType;
 }
 
 } // namespace
 
 #endif