Merge "Revert "Fix user switcher flicker."" into udc-dev am: adf330a1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24328794



Change-Id: I76fd3e238ca8e950744afc2f244a0a72b8c4fcaa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>