diff -r 000000000000 -r 6474c204b198 dom/system/gonk/nsIWorkerHolder.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/system/gonk/nsIWorkerHolder.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+/* 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/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(c04f3102-1ce8-4d57-9c27-8aece9c2740a)]
+interface nsIWorkerHolder : nsISupports
+{
+  readonly attribute jsval worker;
+};