diff -r 000000000000 -r 6474c204b198 toolkit/modules/UpdateChannel.jsm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/modules/UpdateChannel.jsm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+#filter substitution
+
+/* 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/. */
+
+this.EXPORTED_SYMBOLS = ["UpdateChannel"];
+
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+this.UpdateChannel = {
+  /**
+   * Read the update channel from defaults only.  We do this to ensure that
+   * the channel is tightly coupled with the application and does not apply
+   * to other instances of the application that may use the same profile.
+   *
+   * @param [optional] aIncludePartners
+   *        Whether or not to include the partner bits. Default: true.
+   */
+  get: function UpdateChannel_get(aIncludePartners = true) {
+    let channel = "@MOZ_UPDATE_CHANNEL@";
+    let defaults = Services.prefs.getDefaultBranch(null);
+    try {
+      channel = defaults.getCharPref("app.update.channel");
+    } catch (e) {
+      // use default value when pref not found
+    }
+
+    if (aIncludePartners) {
+      try {
+        let partners = Services.prefs.getChildList("app.partner.").sort();
+        if (partners.length) {
+          channel += "-cck";
+          partners.forEach(function (prefName) {
+            channel += "-" + Services.prefs.getCharPref(prefName);
+          });
+        }
+      } catch (e) {
+        Cu.reportError(e);
+      }
+    }
+
+    return channel;
+  }
+};