[DeviceService] Move //device/nfc to be part of the internal impl of Device Service

services/device/public/java/src/org/chromium/device/nfc/NfcDelegate.java

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.device.nfc;
 
 import android.app.Activity;
 
 import org.chromium.base.Callback;
 
 /** Interface that allows the NFC implementation to access the Activity associated with a given
  * client. |hostId| is the same ID passed in NFCProvider::GetNFCForHost().
  */
 public interface NfcDelegate {
     /** Calls |callback| with the Activity associated with |hostId|, and subsequently calls
      * |callback| again whenever the Activity associated with |hostId| changes.
      */
     void trackActivityForHost(int hostId, Callback<Activity> callback);
 
     /** Called when the NFC implementation no longer needs to track the Activity associated with
      * |hostId|.
      */
     void stopTrackingActivityForHost(int hostId);
 }