Merge "Persist screen brightness setting through upgrade" am: 2a747f002f am: a333c1fb5e

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1517740

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I762a6db2c61952d2a8f4fbda511bcc81a870fe81