diff -r 000000000000 -r 6474c204b198 mobile/android/modules/Messaging.jsm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/modules/Messaging.jsm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,44 @@
+/* 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/. */
+"use strict"
+
+const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+this.EXPORTED_SYMBOLS = ["sendMessageToJava"];
+
+XPCOMUtils.defineLazyServiceGetter(this, "uuidgen",
+                                   "@mozilla.org/uuid-generator;1",
+                                   "nsIUUIDGenerator");
+
+function sendMessageToJava(aMessage, aCallback) {
+  if (aCallback) {
+    let id = uuidgen.generateUUID().toString();
+    let obs = {
+      observe: function(aSubject, aTopic, aData) {
+        let data = JSON.parse(aData);
+        if (data.__guid__ != id) {
+          return;
+        }
+
+        Services.obs.removeObserver(obs, aMessage.type + ":Response", false);
+
+        if (data.status === "cancel") {
+          // No Java-side listeners handled our callback.
+          return;
+        }
+
+        aCallback(data.status === "success" ? data.response : null,
+                  data.status === "error"   ? data.response : null);
+      }
+    }
+
+    aMessage.__guid__ = id;
+    Services.obs.addObserver(obs, aMessage.type + ":Response", false);
+  }
+
+  return Services.androidBridge.handleGeckoMessage(aMessage);
+}