Merge "Notify of new top task changes when a top task is moved to the back"...

Merge "Notify of new top task changes when a top task is moved to the back" into tm-dev am: a5bd9061 am: 2d239d9d am: 8ac44d56 am: 7003f709

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18759417



Change-Id: I2819ad312f75b3ea51652672b74ebdf23e1c5fd6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>