51c5dae6bb
When switching users and attempting to lock the device, the sysui main thread becomes overwhelmed with events, creating a significant lag between the time a message is posted and processed on the main thread. This can be dangerous when these events are critical for security, such as calls coming from PhoneWindowManager#lockNow() that call KeyguardViewMediator#doKeyguardTimeout(). On older devices with slower CPUs and less memory, the delay in processing can be significant (15 - 30s). The result of not prioritizing these events leads to a window of time where a guest user can switch back to the owner, and gain access to the owner's homescreen without needing to unlock the device with the owner's credentials. As a mitigation, prioritize two events originating in two specific methods to make sure the device locks as soon as possible as well as have the system server preemptively update its local cache. Bug: 151095871 Test: Very manual race condition - follow steps listed in bug Change-Id: I7585a0a5eeb308e0e32a4f77f581556d883b5cda Merged-In: I7585a0a5eeb308e0e32a4f77f581556d883b5cda (cherry picked from commit28c53ab8bc) (cherry picked from commit21e48cf26b)