[flexiglass] Skip lockscreen when devices wakes.

...if the auth method is None.

Fix: 292502433
Test: manually verified that, with an auth method of None, turning on
the device skips the lockscreen (but the lockscreen _is_ shown when the
device display is asleep - to show AOD).
Test: manually verified that, with a secure auth method (tried pattern),
turning on the device does NOT skip the lockscreen.
Test: added unit tests cases to cover new functionality.

Change-Id: I5d80ff6dc52b4f0dc0e7adf16159df32858f8815