Remove several TetherUtil functions which are no longer needed.

Slowly chipping away at TetherUtil to clean up this code.
This CL also adds an admin check to
ConnectivityService.isTetheringSupported to get parity with the
TetherUtil function before removing it.

Change-Id: Ibe7c5c9fb420d57e5458f77dad30e8a1e751a3e2

services/core/java/com/android/server/ConnectivityService.java

@@ -2670,18 +2670,21 @@ public class ConnectivityService extends IConnectivityManager.Stub
     // if ro.tether.denied = true we default to no tethering
     // gservices could set the secure setting to 1 though to enable it on a build where it
     // had previously been turned off.
+    @Override
     public boolean isTetheringSupported() {
         enforceTetherAccessPermission();
         int defaultVal = (SystemProperties.get("ro.tether.denied").equals("true") ? 0 : 1);
         boolean tetherEnabledInSettings = (Settings.Global.getInt(mContext.getContentResolver(),
                 Settings.Global.TETHER_SUPPORTED, defaultVal) != 0)
                 && !mUserManager.hasUserRestriction(UserManager.DISALLOW_CONFIG_TETHERING);
-        return tetherEnabledInSettings && ((mTethering.getTetherableUsbRegexs().length != 0 ||
+        return tetherEnabledInSettings && mUserManager.isAdminUser() &&
+                ((mTethering.getTetherableUsbRegexs().length != 0 ||
                 mTethering.getTetherableWifiRegexs().length != 0 ||
                 mTethering.getTetherableBluetoothRegexs().length != 0) &&
                 mTethering.getUpstreamIfaceTypes().length != 0);
     }
 
+    @Override
     public void startTethering(int type, ResultReceiver receiver,
             boolean showProvisioningUi) {
         ConnectivityManager.enforceTetherChangePermission(mContext);
@@ -2692,6 +2695,7 @@ public class ConnectivityService extends IConnectivityManager.Stub
         mTethering.startTethering(type, receiver, showProvisioningUi);
     }
 
+    @Override
     public void stopTethering(int type) {
         ConnectivityManager.enforceTetherChangePermission(mContext);
         mTethering.stopTethering(type);