Merge "Do not letterbox the activity in PiP mode" into udc-dev am: 41667fa9da am: 96b03a3f28

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23503609

Change-Id: Ia5958d9c842bbedcd176ef3b6cb418e515073edb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>