Merge "Backup SystemUI as system user" into tm-qpr-dev am: e50b8859a1 am: e03dc901bb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21318345

Change-Id: Ie04a12e4dcfc1c3b2001e0281dca65224c83edd9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>