[automerger skipped] Merge "DO NOT MERGE Handle back button for notification...

[automerger skipped] Merge "DO NOT MERGE Handle back button for notification panel" into rvc-qpr-dev am: 7d4b625c am: d34e379a -s ours am: 01111440

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13408029

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ie9eed5f8150f28d1fe43aee33235788047db2fa5