Merge "Add support to persist app background restriction settings." into tm-dev am: 4935cbc6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17354264



Change-Id: Id3c5917b61a4db5cd2453cb835f7642a98dc217d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>