WHY Nexus 5 Android 6.0 Marshmallow Preview 3 does not "FACE-LOCK"

When Nexus 5 android version 4.1.1 face-lock but Nexus 5 Android 6.0 Marshmallow Preview 3 do not face-lock option why?????/:confused::confused::confused::confused::confused: :confused:



PLEASE ANY SOLUTION I AM WAITING FOR YOUR ANSWER??:good::good::good::good::good::good: