Use ContainerNode type instead of Node for LiveNodeListBase's rootNode

Source/core/html/HTMLCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012 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 266 matching lines @@
 template <> inline bool isMatchingElement(const HTMLTagCollection& collection, const Element& element)
 {
     return collection.elementMatches(element);
 }
 
 template <> inline bool isMatchingElement(const LiveNodeList& nodeList, const Element& element)
 {
     return nodeList.nodeMatches(element);
 }
 
-static Node* previousNode(const Node& base, const Node& previous, bool onlyIncludeDirectChildren)
+static Node* previousNode(const ContainerNode& base, const Node& previous, bool onlyIncludeDirectChildren)
 {
     return onlyIncludeDirectChildren ? previous.previousSibling() : NodeTraversal::previous(previous, &base);
 }
 
-static inline Node* lastDescendant(const Node& node)
+static inline Node* lastDescendant(const ContainerNode& node)
 {
     Node* descendant = node.lastChild();
     for (Node* current = descendant; current; current = current->lastChild())
         descendant = current;
     return descendant;
 }
 
-static Node* lastNode(const Node& rootNode, bool onlyIncludeDirectChildren)
+static Node* lastNode(const ContainerNode& rootNode, bool onlyIncludeDirectChildren)
 {
     return onlyIncludeDirectChildren ? rootNode.lastChild() : lastDescendant(rootNode);
 }
 
 template <typename Collection>
 ALWAYS_INLINE Element* LiveNodeListBase::iterateForPreviousNode(const Collection& collection, Node* current)
 {
     bool onlyIncludeDirectChildren = collection.shouldOnlyIncludeDirectChildren();
-    Node& rootNode = collection.rootNode();
+    ContainerNode& rootNode = collection.rootNode();
     for (; current; current = previousNode(rootNode, *current, onlyIncludeDirectChildren)) {
         if (current->isElementNode() && isMatchingElement(collection, toElement(*current)))
             return toElement(current);
     }
     return 0;
 }
 
 template <typename Collection>
 Element* LiveNodeListBase::itemBefore(const Collection& collection, const Node* previous)
 {
@@ skipping 260 matching lines @@
 
 void HTMLCollection::append(NodeCacheMap& map, const AtomicString& key, Element* element)
 {
     OwnPtr<Vector<Element*> >& vector = map.add(key.impl(), nullptr).iterator->value;
     if (!vector)
         vector = adoptPtr(new Vector<Element*>);
     vector->append(element);
 }
 
 } // namespace WebCore