Async handling of AMS.onUnlockUser

syncSharedAccounts opens CE database and can block ActivityManager
thread for 100+ ms. This operation can be offloaded to a worker thread.

Test: Manual - No "AccountManagerService$Lifecycle took X ms" warnings
Bug: 37579992
Change-Id: Ie517722efe37da7c6782144beccdad53b047770b
1 file changed