Merge ""Merge" activity-only transitions into ongoing recents" into udc-dev...

Merge ""Merge" activity-only transitions into ongoing recents" into udc-dev am: 6a7dca36 am: 8139f7c0

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22183106



Change-Id: Ief4be8b53b79049d9aaa47ad67f1763451d000e4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>