Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

Source/core/dom/EmptyNodeList.h

 /*
+ * Copyright (C) 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  */
 
-#ifndef SVGDiscardElement_h
-#define SVGDiscardElement_h
+#ifndef EmptyNodeList_h
+#define EmptyNodeList_h
 
-#include "core/svg/animation/SVGSMILElement.h"
+#include "core/dom/NodeList.h"
 
 namespace WebCore {
 
-class SVGDiscardElement FINAL : public SVGSMILElement {
+class EmptyNodeList FINAL : public NodeList {
 public:
-    static PassRefPtr<SVGDiscardElement> create(Document&);
+    static PassRefPtr<EmptyNodeList> create(Node* rootNode)
+    {
+        return adoptRef(new EmptyNodeList(rootNode));
+    }
+    virtual ~EmptyNodeList();
 
-    virtual bool isSVGDiscardElement() const OVERRIDE { return true; }
+    Node* ownerNode() const { return m_owner.get(); }
+
 private:
-    explicit SVGDiscardElement(Document&);
+    explicit EmptyNodeList(Node* rootNode) : m_owner(rootNode) { }
 
-    virtual void resetAnimatedType() OVERRIDE { }
-    virtual void clearAnimatedType(SVGElement* targetElement) OVERRIDE { }
-    virtual void applyResultsToTarget() OVERRIDE { }
-    virtual bool hasValidAttributeType() OVERRIDE;
-    virtual bool hasValidAttributeName() OVERRIDE;
-    virtual void animationAttributeChanged() OVERRIDE { }
+    virtual unsigned length() const OVERRIDE { return 0; }
+    virtual Node* item(unsigned) const OVERRIDE { return 0; }
+    virtual Node* namedItem(const AtomicString&) const OVERRIDE { return 0; }
 
-    virtual void startedActiveInterval() OVERRIDE { }
-    virtual void updateAnimation(float percent, unsigned repeat, SVGSMILElement* resultElement) OVERRIDE { }
+    virtual bool isEmptyNodeList() const OVERRIDE { return true; }
+
+    RefPtr<Node> m_owner;
 };
 
+DEFINE_TYPE_CASTS(EmptyNodeList, NodeList, nodeList, nodeList->isEmptyNodeList(), nodeList.isEmptyNodeList());
+
 } // namespace WebCore
 
-#endif // SVGDiscardElement_h
+#endif // EmptyNodeList_h