It's lights out for you, navigation bar!

Views requesting lights out mode will cause the navbar to
disappear (this is useful for viewing videos/photos/etc
using every pixel of the screen).

But there's a catch: any user activity at all will cause the
lights to come back on and the navbar to return.

Change-Id: I535ed3ba9ae7fab3282c402be256add765395b6f
10 files changed