Bug 1179685 - Fix messageport assert in wpt service worker test. r=baku

dom/workers/ServiceWorkerClient.cpp

@@ -129,10 +129,11 @@ private:
     closure.mClonedObjects.SwapElements(mClosure.mClonedObjects);
     MOZ_ASSERT(mClosure.mMessagePorts.IsEmpty());
     closure.mMessagePortIdentifiers.SwapElements(mClosure.mMessagePortIdentifiers);
+    closure.mParentWindow = do_QueryInterface(aTargetContainer->GetParentObject());
 
     JS::Rooted<JS::Value> messageData(aCx);
     if (!mBuffer.read(aCx, &messageData,
-                      WorkerStructuredCloneCallbacks(true))) {
+                      WorkerStructuredCloneCallbacks(true), &closure)) {
       xpc::Throw(aCx, NS_ERROR_DOM_DATA_CLONE_ERR);
       return NS_ERROR_FAILURE;
     }

testing/web-platform/mozilla/tests/service-workers/service-worker/postmessage-msgport-to-client.https.html

@@ -15,7 +15,7 @@ t.step(function() {
       .then(function() { return with_iframe(scope); })
       .then(function(frame) {
           var w = frame.contentWindow;
-          w.onmessage = t.step_func(onMessage);
+          w.navigator.serviceWorker.onmessage = t.step_func(onMessage);
           w.navigator.serviceWorker.controller.postMessage('ping');
         })
       .catch(unreached_rejection(t));