Defer hiding Keyguard if in sleeping mode

Regardless of whether Security is enabled or not, Keyguard should always
be activated when the device is in sleeping mode and it should suppress
gesture events that can cause the screen being turned back on.

Bug: 194912008
Bug: 194115621
Test: Manual + Unit Tests + CTS
(atest android.server.wm.MultiDisplayPolicyTests#testExternalDisplayActivityTurnPrimaryOff)
Change-Id: I89cc8e69fcd88e5ff7fc1815e910b4b9545a6de7
2 files changed