Make IKeyguardService interface asynchronous

Add a state callback so lockscreen reports back whenever its state
relevant for PhoneWindowManager changed, instead of synchronously
calling into SysUI which can lead to deadlocks. Directly use
LockPatternUtils for isSecure, and optimize the number of calls to
this method to optimize layout performance.

Bug: 17677097
Change-Id: I5d491fc8884d4f84d9562626b9ea0d5eaa5166fc