Merge "Fix the activity enter / exit animation." into udc-dev am: 0209aeede5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22778356

Change-Id: I802fbbb52968b10f180fc187b351c3e3936a177d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>