Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

Source/core/dom/NodeList.cpp

Index: Source/core/dom/NodeList.cpp
diff --git a/Source/core/dom/NodeList.cpp b/Source/core/dom/NodeList.cpp
index 2666ba44f2d08c2ea56a4e6d30e2336600345481..e86640a810c23f69c30ced276e410ec93810ea76 100644
--- a/Source/core/dom/NodeList.cpp
+++ b/Source/core/dom/NodeList.cpp
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "core/dom/NodeList.h"
 
+#include "core/dom/EmptyNodeList.h"
 #include "core/dom/LiveNodeList.h"
 #include "core/dom/Node.h"
 
@@ -58,6 +59,8 @@ Node* NodeList::ownerNode() const
 {
     if (isLiveNodeList())
         return static_cast<const LiveNodeList*>(this)->ownerNode();
+    if (isEmptyNodeList())
+        return static_cast<const EmptyNodeList*>(this)->ownerNode();
     return 0;
 }