Add gn implementation for //components/keyed_service/ios.

components/keyed_service.gypi

 # Copyright 2014 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.
 
 {
   'targets': [
     {
       # GN version: //components/keyed_service/core:core
       'target_name': 'keyed_service_core',
       'type': '<(component)',
@@ skipping 64 matching lines @@
             'keyed_service/content/browser_context_keyed_service_shutdown_notifier_factory.cc',
             'keyed_service/content/browser_context_keyed_service_shutdown_notifier_factory.h',
             'keyed_service/content/refcounted_browser_context_keyed_service_factory.cc',
             'keyed_service/content/refcounted_browser_context_keyed_service_factory.h',
         ],
       }],
     }],
     ['OS == "ios"', {
       'targets': [
         {
+          # GN version: //components/keyed_service/ios
           'target_name': 'keyed_service_ios',
           'type': '<(component)',
           'defines': [
             'KEYED_SERVICE_IMPLEMENTATION',
           ],
           'dependencies': [
             '../base/base.gyp:base',
             '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
             '../ios/web/ios_web.gyp:ios_web',
             'keyed_service_core',
           ],
           'include_dirs': [
             '..',
           ],
           'sources': [
             'keyed_service/ios/browser_state_context_converter.cc',
             'keyed_service/ios/browser_state_context_converter.h',
             'keyed_service/ios/browser_state_dependency_manager.cc',
             'keyed_service/ios/browser_state_dependency_manager.h',
             'keyed_service/ios/browser_state_keyed_service_factory.cc',
             'keyed_service/ios/browser_state_keyed_service_factory.h',
             'keyed_service/ios/refcounted_browser_state_keyed_service_factory.cc',
             'keyed_service/ios/refcounted_browser_state_keyed_service_factory.h',
         ],
       }],
     }],
   ],
 }