Bug 902714 - Add {add,remove}WeakMessageListener to nsIMessageManager. r=smaug
Bug 902714 - Test for nsIMessageManager.addWeakMessageListener. r=smaug, a=leo+
Bug 900221 - Part 0: Add Ci.nsISupportsWeakReference to applicable JS classes. r=fabrice

This is a b2g18-only patch; these changes landed on trunk as part of bug 889984.
Bug 900221 - Part 1: Switch DOMRequestHelper over to using weak message listeners. rs=fabrice, a=leo+