Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

Source/core/dom/ContainerNode.h

Index: Source/core/dom/ContainerNode.h
diff --git a/Source/core/dom/ContainerNode.h b/Source/core/dom/ContainerNode.h
index 82cf472ae2b52830074a4d167cf2b9a3dc03212e..9ce5554b9e2324639aa47154b2877f0df6326859 100644
--- a/Source/core/dom/ContainerNode.h
+++ b/Source/core/dom/ContainerNode.h
@@ -101,6 +101,12 @@ public:
     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<NodeList> getElementsByName(const AtomicString& elementName);
+    PassRefPtr<NodeList> 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.