Bug 823798 - Route FM radio through analog path. r=mwu a=blocking-b2g
Bug 828780 - Ensure that closing a window via closing the last tab goes through the code path taken by closing the window directly; r=gavin

As a result, we make sure that the last-pb-context-exiting notification
is correctly dispatched no matter how we close the last private window.

--HG--
extra : rebase_source : f8bc848b6e86b6f7f5839156613c2e194807c403