diff -r 000000000000 -r 6474c204b198 browser/metro/base/tests/mochiperf/msgmanagerecho.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/metro/base/tests/mochiperf/msgmanagerecho.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * TestEchoReceiver - receives json data, reserializes it and send it back.
+ */ 
+
+"use strict";
+
+var TestEchoReceiver = {
+  init: function init() {
+    addMessageListener("Test:EchoRequest", this);
+  },
+
+  receiveMessage: function receiveMessage(aMessage) {
+    let json = aMessage.json;
+    switch (aMessage.name) {
+      case "Test:EchoRequest":
+        sendAsyncMessage("Test:EchoResponse", json);
+        break;
+    }
+  },
+
+};
+
+TestEchoReceiver.init();
+