Merge "Revert "Fix user switcher flicker."" into udc-dev am: adf330a1 am: 7498c0d9

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



Change-Id: I8ab49744a90a0e303bc44e88db2d2f0eab6a6e2f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>