When unregistering, if the caller process is dead. The system can unregsiter for the caller. But the request decrement should be counted onto the caller uid instead of system uid. Test: NetworkStatsObserversTest#testUnregister_knownRequest_invalidUid_doesNotUnregister Bug: 233580307 Change-Id: I85aee8f395739929bc7086883ace81ac1ecd0730 Merged-In: I85aee8f395739929bc7086883ace81ac1ecd0730 (pure cherry-picked from ag/18579047)