Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

Source/core/dom/EmptyNodeList.h

Index: Source/core/dom/EmptyNodeList.h
diff --git a/Source/core/svg/SVGDiscardElement.h b/Source/core/dom/EmptyNodeList.h
old mode 100755
new mode 100644
similarity index 64%
copy from Source/core/svg/SVGDiscardElement.h
copy to Source/core/dom/EmptyNodeList.h
index 653a1db94ebf2acb389f89122027bfc7fdc4f0d3..a505aaa08b04f48bee3903622ddfb89667554516
--- a/Source/core/svg/SVGDiscardElement.h
+++ b/Source/core/dom/EmptyNodeList.h
@@ -1,4 +1,5 @@
 /*
+ * 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
@@ -28,32 +29,37 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#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();
+
+    Node* ownerNode() const { return m_owner.get(); }
 
-    virtual bool isSVGDiscardElement() const OVERRIDE { return true; }
 private:
-    explicit SVGDiscardElement(Document&);
+    explicit EmptyNodeList(Node* rootNode) : m_owner(rootNode) { }
+
+    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 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 bool isEmptyNodeList() const OVERRIDE { return true; }
 
-    virtual void startedActiveInterval() OVERRIDE { }
-    virtual void updateAnimation(float percent, unsigned repeat, SVGSMILElement* resultElement) OVERRIDE { }
+    RefPtr<Node> m_owner;
 };
 
+DEFINE_TYPE_CASTS(EmptyNodeList, NodeList, nodeList, nodeList->isEmptyNodeList(), nodeList.isEmptyNodeList());
+
 } // namespace WebCore
 
-#endif // SVGDiscardElement_h
+#endif // EmptyNodeList_h