diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/util/uuid.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/lib/sdk/util/uuid.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+/* 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";
+
+module.metadata = {
+  "stability": "unstable"
+};
+
+const { Cc, Ci, components: { ID: parseUUID } } = require('chrome');
+const { generateUUID } = Cc['@mozilla.org/uuid-generator;1'].
+                          getService(Ci.nsIUUIDGenerator);
+
+// Returns `uuid`. If `id` is passed then it's parsed to `uuid` and returned
+// if not then new one is generated.
+exports.uuid = function uuid(id) id ? parseUUID(id) : generateUUID()