(2/n) Stop user from enabling OHM setting if user is using 3-button

mode

Return One-Handed mode getAvailabilityStatus to UNSUPPORTED_ON_DEVICE
when SystemNavigationMode is 3-button.

Bug: 184903678

Test: manual
Test: manual verified on Settings > System > Gesture page
Test: make RunSettingsRoboTests ROBOTEST_FILTER=
      "com.android.settings.gestures
      .OneHandedEnablePreferenceControllerTest"
Test: make RunSettingsRoboTests ROBOTEST_FILTER=
      "com.android.settings.gestures
      .SwipeBottomToNotificationPreferenceControllerTest"
Change-Id: I454dabb5cc267d544732fa5079f3146154d0568c

src/com/android/settings/gestures/OneHandedSettingsUtils.java

@@ -176,6 +176,28 @@ public class OneHandedSettingsUtils {
                 sCurrentUserId);
     }
 
+    /**
+     * Get NavigationBar mode flag from Settings provider.
+     * @param context App context
+     * @return Navigation bar mode:
+     *  0 = 3 button
+     *  1 = 2 button
+     *  2 = fully gestural
+     */
+    public static int getNavigationBarMode(Context context) {
+        return Settings.Secure.getIntForUser(context.getContentResolver(),
+                Settings.Secure.NAVIGATION_MODE, 2 /* fully gestural */, sCurrentUserId);
+    }
+
+    /**
+     *
+     * @param context App context
+     * @return Support One-Handed mode feature or not.
+     */
+    public static boolean isFeatureAvailable(Context context) {
+        return isSupportOneHandedMode() && getNavigationBarMode(context) != 0;
+    }
+
     /**
      * Registers callback for observing Settings.Secure.ONE_HANDED_MODE_ENABLED state.
      * @param callback for state changes