[Settings] Support getSystemService(Class<T>)

Add getSystemService(Class<T>) to align the capability with framework
part.

This is a back port from aosp/1639943, aosp/1645152 and aosp/1648047

Bug: 179640862
Test: local
Change-Id: I035db55a71f94000ca35f8d71f03c19208423c73

src/com/android/settings/deviceinfo/DeviceNamePreferenceController.java

@@ -58,7 +58,7 @@ public class DeviceNamePreferenceController extends BasePreferenceController
     public DeviceNamePreferenceController(Context context, String key) {
         super(context, key);
 
-        mWifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
+        mWifiManager = context.getSystemService(WifiManager.class);
         mWifiDeviceNameTextValidator = new WifiDeviceNameTextValidator();
         mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();