Merge "Minor changes on AccessibilityManagerService for visible bg users:" into udc-dev am: 6a2dd9b9 am: 23810caa

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22717336



Change-Id: Id32beced99b18a11917f66efb4010de6eebf3e6c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>