Merge "DO NOT MERGE Intercept back button on user switcher screen" into rvc-qpr-dev am: de0869335a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13689637

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I01f2dcbbb43e75cecf7d21dd9967b07087aa8a55