Merge "Updating SysUI state when back enabled/disabled state change" into...

Merge "Updating SysUI state when back enabled/disabled state change" into rvc-dev am: d71e76fd am: 58789f6c am: 3f4d8fe3 am: 998e36e6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11965840

Change-Id: Ia7fe1997d700c6b92e5122bee1364a6c115b913e