Restore immersive mode when volume button has been pressed.

Workaround issue where SYSTEM_UI_FLAG_IMMERSIVE_STICKY is invalidated
when a volume button is pressed (internal bug ref b/11986621)

Immersive mode still does not recover when the screen has been
rotated, due to onSystemUiVisibilityChange is not triggered
when screen is rotated (internal bug ref b/11990702)

Change-Id: Ifdfe9b24d5c3c208441aeca0fbb2b1eaee39da95
2 files changed