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

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



Change-Id: I20d6ed28795838335aff77b43009d658bafee496
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>