Merge "Fix the activity enter / exit animation." into udc-dev am: 0209aeed am: a842d1dd am: b9c1061e

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



Change-Id: I37841421125373f62f7177408a536c8642245059
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>