diff -r 000000000000 -r 6474c204b198 dom/activities/src/ActivityWrapper.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/activities/src/ActivityWrapper.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,91 @@
+/* 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 Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+
+XPCOMUtils.defineLazyServiceGetter(this, "cpmm",
+                                   "@mozilla.org/childprocessmessagemanager;1",
+                                   "nsISyncMessageSender");
+
+function debug(aMsg) {
+  //dump("-- ActivityWrapper.js " + Date.now() + " : " + aMsg + "\n");
+}
+
+/**
+  * nsISystemMessagesWrapper implementation. Will return a
+  * nsIDOMMozActivityRequestHandler
+  */
+function ActivityWrapper() {
+  debug("ActivityWrapper");
+}
+
+ActivityWrapper.prototype = {
+  wrapMessage: function wrapMessage(aMessage, aWindow) {
+    debug("Wrapping " + JSON.stringify(aMessage));
+
+    // This message is useful to communicate that the activity message has been
+    // properly received by the app. If the app will be killed, the
+    // ActivitiesService will be able to fire an error and complete the
+    // Activity workflow.
+    cpmm.sendAsyncMessage("Activity:Ready", { id: aMessage.id });
+
+    let handler = new aWindow.ActivityRequestHandler(aMessage.id, aMessage.payload);
+
+    // When the activity window is closed, fire an error to notify the activity
+    // caller of the situation.
+    // We don't need to check whether the activity itself already sent
+    // back something since ActivitiesService.jsm takes care of that.
+    let util = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
+                      .getInterface(Ci.nsIDOMWindowUtils);
+    let innerWindowID = util.currentInnerWindowID;
+
+    let observer = {
+      observe: function(aSubject, aTopic, aData) {
+
+        switch (aTopic) {
+          case 'inner-window-destroyed':
+            let wId = aSubject.QueryInterface(Ci.nsISupportsPRUint64).data;
+            if (wId == innerWindowID) {
+              debug("Closing activity window " + innerWindowID);
+              Services.obs.removeObserver(observer, "inner-window-destroyed");
+              cpmm.sendAsyncMessage("Activity:PostError",
+                                    { id: aMessage.id,
+                                      error: "ActivityCanceled"
+                                    });
+            }
+            break;
+          case 'activity-error':
+          case 'activity-success':
+            if (aData !== aMessage.id) {
+              return;
+            }
+            Services.obs.removeObserver(observer, "activity-error");
+            Services.obs.removeObserver(observer, "activity-success");
+            let docshell = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
+                                  .getInterface(Ci.nsIWebNavigation);
+            Services.obs.notifyObservers(docshell, "activity-done", aTopic);
+            break;
+        }
+      }
+    }
+
+    Services.obs.addObserver(observer, "activity-error", false);
+    Services.obs.addObserver(observer, "activity-success", false);
+    Services.obs.addObserver(observer, "inner-window-destroyed", false);
+    return handler;
+  },
+
+  classID: Components.ID("{5430d6f9-32d6-4924-ba39-6b6d1b093cd6}"),
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsISystemMessagesWrapper])
+}
+
+this.NSGetFactory = XPCOMUtils.generateNSGetFactory([ActivityWrapper]);
+