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: d5cc5aa1

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



Change-Id: I72f14908508460cb50a1367c4dbfe43bbc0f8eb5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>