[webnfc] Add default implementation for nfc mojo service.

device/nfc/nfc.gyp

 # Copyright 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 42 matching lines @@
     {
       'target_name': 'device_nfc_mojo_bindings',
       'type': 'static_library',
       'includes': [
         '../../mojo/mojom_bindings_generator.gypi',
       ],
       'sources': [
         'nfc.mojom',
       ],
     },
+    {
+      # GN version: //device/nfc_mojo
+      'target_name': 'device_nfc_mojo',
+      'type': '<(component)',
+      'dependencies': [
+        '../../base/base.gyp:base',
+        '../../mojo/mojo_edk.gyp:mojo_system_impl',
+        '../../mojo/mojo_public.gyp:mojo_cpp_bindings',
+        'device_nfc_mojo_bindings',
+      ],
+      'defines': [
+        'DEVICE_NFC_IMPLEMENTATION',
+      ],
+      'sources': [
+        'nfc_impl_default.cc',
+        'nfc_impl.h',
+      ],
+    },
   ],
 }