Allows the user to toggle
Settings.Secure.LOCK_SCREEN_ALLOW_PRIVATE_NOTIFICATIONS,
which if set shows the complete private contents of that
user's notifications atop a securely locked screen. When
unset, only the "public" versions of notifications are shown
(which may include explicit redactions made by the app).
See f/b change I32bb7939 for details.
This checkbox is hidden for insecure keyguards ("off" and
"none"). It is also unavailable if
Settings.Global.LOCK_SCREEN_SHOW_NOTIFICATIONS is not set
(see f/b change I9c517949.)
Change-Id: Ie1b4c6b949b597b97e536d8ea7e35c9de9b6995f
91d014a965