Reset VPN settings by calling VpnManager.

Currently, ConnectivityManager#factoryReset calls
VpnManager#factoryReset. Call the VpnManager method directly so
it can be removed from ConnectivityManager.

Bug: 173331190
Test: atest SettingsRoboTests
Change-Id: I7c702a627cd448dbde40e0d885fbc570ecd1e55d

src/com/android/settings/ResetNetworkConfirm.java

@@ -28,6 +28,7 @@ import android.content.Context;
 import android.net.ConnectivityManager;
 import android.net.NetworkPolicyManager;
 import android.net.Uri;
+import android.net.VpnManager;
 import android.net.wifi.WifiManager;
 import android.net.wifi.p2p.WifiP2pManager;
 import android.os.AsyncTask;
@@ -93,6 +94,11 @@ public class ResetNetworkConfirm extends InstrumentedFragment {
                 connectivityManager.factoryReset();
             }
 
+            VpnManager vpnManager = mContext.getSystemService(VpnManager.class);
+            if (vpnManager != null) {
+                vpnManager.factoryReset();
+            }
+
             WifiManager wifiManager = (WifiManager)
                     mContext.getSystemService(Context.WIFI_SERVICE);
             if (wifiManager != null) {