To be the unbundled application, tethering can not use UserManagerInternal method anymore. Replace it by listening user restriction change intent. Also fix some cleanup from https://android-review.googlesource.com/c/platform/frameworks/base/+/1131002 Bug: 143195885 Test: -build, flash, boot -atest TetheringTests -manual test. Add a trigger point to call UserManager.setUserRestriction(DISALLOW_CONFIG_TETHERING) from Settings. Open hotspot -> restrict tethering from new adding trigger point -> hotspot is OFF and Tethering settings are not available. Change-Id: I4ed08d20f8b7476b8ecd5d018b75806dd2f22cc1