Merge "Merge "Add a callback to listen to uid foreground-ness change." into udc-dev am: b0302b10 am: 179cad08 am: 827e4168" into udc-qpr-dev-plus-aosp am: 4d16e0be

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22499498



Change-Id: I08c7b227e7c0224a0d9fc2b98da446d4c2bfbba8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>