Merge "Polish entering pip from fullscreen with shell transition" into udc-dev...

Merge "Polish entering pip from fullscreen with shell transition" into udc-dev am: 16e51ba1 am: 81769e64 am: 75f6a41d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22952408



Change-Id: I8280ed448f634e44cffaa80c3031c97ec471d0f2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>