LockIcon fixes

Gather state inisitally, then consolidate it on a pre-draw listener.
Before we were deciding when to change the icon based on various
variables, now I'm centralizing the decision on getState(), to avoid
cancelling animations.

Test: At AOD2, lock animates in
Test: When locked, press power button: lock icon animates in
Test: Press power button: lock icon animates in scanning and unlocks
Test: Unlock without bypassing, let device sleep, go to AOD2
Test: Long press padlock when it's open
Test: Look at padlock from SIM PIN screen
Test: Look at padlock when lock screen is not secure (no pin/pwd)
Fixes: 135587352
Fixes: 135960400
Change-Id: I85260b6c373d675bd6076046e33519816221157f