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: 85ba9133 am: 4b130407

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



Change-Id: I779e32dffa1f9694a0c0a582dcc9b574f8d035ca
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>