SystemUI: Expose heads up.

Signed-off-by: Roman Birg <roman@cyngn.com>
Signed-off-by: Adnan Begovic <adnan@cyngn.com>
Change-Id: I276cb1c80d392b7dbac28e5f553207415b558481
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0