Make NodeList::ownerNode() virtual and rename to virtualOwnerNode()

Source/core/dom/EmptyNodeList.h

Index: Source/core/dom/EmptyNodeList.h
diff --git a/Source/core/dom/EmptyNodeList.h b/Source/core/dom/EmptyNodeList.h
index 7c26d6064aa953a707e47a70926dc260b206f9f0..06f895fac86e0471a8aa0f83a1590c90d28ce8af 100644
--- a/Source/core/dom/EmptyNodeList.h
+++ b/Source/core/dom/EmptyNodeList.h
@@ -53,6 +53,7 @@ private:
     virtual Node* item(unsigned) const OVERRIDE { return 0; }
 
     virtual bool isEmptyNodeList() const OVERRIDE { return true; }
+    virtual Node* virtualOwnerNode() const OVERRIDE;
 
     RefPtr<Node> m_owner;
 };