Add chrome/service to GN build.

chrome/chrome.gyp

 # Copyright (c) 2012 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,
 
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
     # the link of the actual chrome (or chromium) executable on
@@ skipping 668 matching lines @@
       'includes': [
         'chrome_android.gypi',
       ]}, # 'includes'
     ],  # OS=="android"
     ['configuration_policy==1 and OS!="android" and OS!="ios"', {
       'includes': [ 'policy.gypi', ],
     }],
     ['enable_printing==1', {
       'targets': [
         {
+          # GN version: //chrome/service
           'target_name': 'service',
           'type': 'static_library',
           'variables': { 'enable_wexit_time_destructors': 1, },
           'dependencies': [
             'chrome_resources.gyp:chrome_strings',
             'common',
             'common_net',
             '../base/base.gyp:base',
             '../components/components.gyp:cloud_devices_common',
             '../google_apis/google_apis.gyp:google_apis',
             '../jingle/jingle.gyp:notifier',
             '../net/net.gyp:net',
             '../printing/printing.gyp:printing',
             '../skia/skia.gyp:skia',
             '../third_party/libjingle/libjingle.gyp:libjingle',
           ],
           'sources': [
+            # Note: sources list duplicated in GN build.
             'service/cloud_print/cdd_conversion_win.cc',
             'service/cloud_print/cdd_conversion_win.h',
             'service/cloud_print/cloud_print_auth.cc',
             'service/cloud_print/cloud_print_auth.h',
             'service/cloud_print/cloud_print_connector.cc',
             'service/cloud_print/cloud_print_connector.h',
             'service/cloud_print/cloud_print_proxy.cc',
             'service/cloud_print/cloud_print_proxy.h',
             'service/cloud_print/cloud_print_proxy_backend.cc',
             'service/cloud_print/cloud_print_proxy_backend.h',
@@ skipping 44 matching lines @@
               'sources': [
                 'service/cloud_print/print_system_dummy.cc',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }