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: Ic99b0ae4b2be9db1c5a6e5e35e4e386cd4761ea0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>