Lock access to managed services.

Fixes: 35873807
Test: manual, set a notification to enqueue once a second for a few
minutes while also repeatedly granting and denying notification listener
access to a couple of apps in Settings and verifying
that nothing crashes and log is clean.

Change-Id: I15f429d61bf5f9ad639e524a94288a6d2db2cb56
3 files changed