Add Secure setting for the assist gesture.

Test: make
Change-Id: I21c88c0b91043db3de46830044c434a21a0e6cc0

core/java/android/provider/Settings.java

@@ -6691,6 +6691,13 @@ public final class Settings {
         public static final String CAMERA_DOUBLE_TWIST_TO_FLIP_ENABLED =
                 "camera_double_twist_to_flip_enabled";
 
+        /**
+         * Whether the assist gesture should be enabled.
+         *
+         * @hide
+         */
+        public static final String ASSIST_GESTURE_ENABLED = "assist_gesture_enabled";
+
         /**
          * Control whether Night display is currently activated.
          * @hide
@@ -6942,7 +6949,8 @@ public final class Settings {
             DOZE_PULSE_ON_PICK_UP,
             DOZE_PULSE_ON_DOUBLE_TAP,
             NFC_PAYMENT_DEFAULT_COMPONENT,
-            AUTOMATIC_STORAGE_MANAGER_DAYS_TO_RETAIN
+            AUTOMATIC_STORAGE_MANAGER_DAYS_TO_RETAIN,
+            ASSIST_GESTURE_ENABLED
         };
 
         /**