Use existing content resolver

See b/153347449 for possible
future changes

Fixes: 153338799
Change-Id: I1cc918742ded98d44adfd44b5e6e247f2b71b6a7

packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java

@@ -635,7 +635,7 @@ public class NavigationBarFragment extends LifecycleFragment implements Callback
     }
 
     private void updatedFixedRotation() {
-        mFixedRotationEnabled = Settings.Global.getInt(getContext().getContentResolver(),
+        mFixedRotationEnabled = Settings.Global.getInt(mContentResolver,
                 FIXED_ROTATION_TRANSFORM_SETTING_NAME, 0) != 0;
         if (!canShowSecondaryHandle()) {
             resetSecondaryHandle();