Fixing Node.clone returning non-upgraded Dart custom elements.

Source/bindings/dart/custom/DartNodeCustom.cpp

Index: Source/bindings/dart/custom/DartNodeCustom.cpp
diff --git a/Source/bindings/dart/custom/DartNodeCustom.cpp b/Source/bindings/dart/custom/DartNodeCustom.cpp
index a3722a5274a9ba0f34f2bd9e93ebf594bdb94b44..ab2ed7ff4f8b8928aa0d9e97c376e5e036c46f9d 100644
--- a/Source/bindings/dart/custom/DartNodeCustom.cpp
+++ b/Source/bindings/dart/custom/DartNodeCustom.cpp
@@ -43,6 +43,7 @@
 #include "DartProcessingInstruction.h"
 #include "DartText.h"
 #include "bindings/dart/DartDOMWrapper.h"
+#include "core/dom/CustomElementCallbackDispatcher.h"
 
 namespace WebCore {
 
@@ -164,6 +165,32 @@ fail:
     ASSERT_NOT_REACHED();
 }
 
+void cloneNodeCallback(Dart_NativeArguments args)
+{
+    Dart_Handle exception = 0;
+    {
+        Node* receiver = DartDOMWrapper::receiver< Node >(args);
+
+        bool deep = DartUtilities::dartToBool(args, 1, exception);
+        if (exception)
+            goto fail;
+
+        RefPtr<Node> result;
+        {
+            CustomElementCallbackDispatcher::CallbackDeliveryScope deliveryScope;
+
+            result = receiver->cloneNode(deep);
+        }
+
+        DartNode::returnToDart(args, result);
+        return;
+    }
+
+fail:
+    Dart_ThrowException(exception);
+    ASSERT_NOT_REACHED();
+}
+
 }
 
 Dart_Handle DartNode::createWrapper(Node* node)