1. Views may setSystemUiVisibility() to recommend that
the system chrome (status bar or other UI) show or hide
itself. (This functionality was previously available only
via the FLAG_FULLSCREEN window flag for some SystemUI
implementations.)
2. Views may register a OnSystemUiVisibilityChangedListener
on a view, and find out when the system UI actually
appears or disappears, allowing apps to coordinate the
appearance of their own UI if desired.
Bug: 3241144
Change-Id: Ia1758d94099182d49a1e3688ea2738ae4995b829
664644d9e0