Merge "Notify organizer when the last activity in TaskFragment enter PiP" into tm-dev am: 88671a050f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17713423

Change-Id: If7c315659887740f520ac5f53125a21971bda37f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>