Added secure setting for face re enrollment.

Test: Verified that the flag could be modified with
adb shell settings put secure...
Bug: 141380252

Change-Id: Ifa24b688a487482e5b02689c1046d85423f73280

core/java/android/provider/Settings.java

@@ -8361,6 +8361,19 @@ public final class Settings {
         private static final Validator FACE_UNLOCK_ALWAYS_REQUIRE_CONFIRMATION_VALIDATOR =
                 BOOLEAN_VALIDATOR;
 
+        /**
+         * Whether or not a user should re enroll their face.
+         *
+         * Face unlock re enroll.
+         *  0 = No re enrollment.
+         *  1 = Re enrollment is suggested.
+         *  2 = Re enrollment is required after a set time period.
+         *  3 = Re enrollment is required immediately.
+         *
+         * @hide
+         */
+        public static final String FACE_UNLOCK_RE_ENROLL = "face_unlock_re_enroll";
+
         /**
          * Whether or not debugging is enabled.
          * @hide

core/tests/coretests/src/android/provider/SettingsBackupTest.java

@@ -722,7 +722,8 @@ public class SettingsBackupTest {
                  Settings.Secure.LOCATION_ACCESS_CHECK_DELAY_MILLIS,
                  Settings.Secure.BIOMETRIC_DEBUG_ENABLED,
                  Settings.Secure.FACE_UNLOCK_ATTENTION_REQUIRED,
-                 Settings.Secure.FACE_UNLOCK_DIVERSITY_REQUIRED);
+                 Settings.Secure.FACE_UNLOCK_DIVERSITY_REQUIRED,
+                 Settings.Secure.FACE_UNLOCK_RE_ENROLL);
 
     @Test
     public void systemSettingsBackedUpOrBlacklisted() {