diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/tab/events.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/lib/sdk/tab/events.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,70 @@
+/* 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";
+
+// This module provides temporary shim until Bug 843901 is shipped.
+// It basically registers tab event listeners on all windows that get
+// opened and forwards them through observer notifications.
+
+module.metadata = {
+  "stability": "experimental"
+};
+
+const { Ci } = require("chrome");
+const { windows, isInteractive } = require("../window/utils");
+const { events } = require("../browser/events");
+const { open } = require("../event/dom");
+const { filter, map, merge, expand } = require("../event/utils");
+const isFennec = require("sdk/system/xul-app").is("Fennec");
+
+// Module provides event stream (in nodejs style) that emits data events
+// for all the tab events that happen in running firefox. At the moment
+// it does it by registering listeners on all browser windows and then
+// forwarding events when they occur to a stream. This will become obsolete
+// once Bug 843901 is fixed, and we'll just leverage observer notifications.
+
+// Set of tab events that this module going to aggregate and expose.
+const TYPES = ["TabOpen","TabClose","TabSelect","TabMove","TabPinned",
+               "TabUnpinned"];
+
+// Utility function that given a browser `window` returns stream of above
+// defined tab events for all tabs on the given window.
+function tabEventsFor(window) {
+  // Map supported event types to a streams of those events on the given
+  // `window` and than merge these streams into single form stream off
+  // all events.
+  let channels = TYPES.map(function(type) open(window, type));
+  return merge(channels);
+}
+
+// Filter DOMContentLoaded events from all the browser events.
+let readyEvents = filter(events, function(e) e.type === "DOMContentLoaded");
+// Map DOMContentLoaded events to it's target browser windows.
+let futureWindows = map(readyEvents, function(e) e.target);
+// Expand all browsers that will become interactive to supported tab events
+// on these windows. Result will be a tab events from all tabs of all windows
+// that will become interactive.
+let eventsFromFuture = expand(futureWindows, tabEventsFor);
+
+// Above covers only windows that will become interactive in a future, but some
+// windows may already be interactive so we pick those and expand to supported
+// tab events for them too.
+let interactiveWindows = windows("navigator:browser", { includePrivate: true }).
+                         filter(isInteractive);
+let eventsFromInteractive = merge(interactiveWindows.map(tabEventsFor));
+
+
+// Finally merge stream of tab events from future windows and current windows
+// to cover all tab events on all windows that will open.
+let allEvents = merge([eventsFromInteractive, eventsFromFuture]);
+
+// Map events to Fennec format if necessary
+exports.events = map(allEvents, function (event) {
+  return !isFennec ? event : {
+    type: event.type,
+    target: event.target.ownerDocument.defaultView.BrowserApp
+            .getTabForBrowser(event.target)
+  };
+});