Add support for building "ios_chrome_unittests" with gn.

ios/chrome/ios_chrome_resources.gyp

 # Copyright 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,
     'grit_base_dir': '<(SHARED_INTERMEDIATE_DIR)',
     'grit_out_dir': '<(grit_base_dir)/ios/chrome',
     'ui_string_overrider_inputs': [
@@ skipping 22 matching lines @@
   'targets': [
     {
       'target_name': 'ios_chrome_resources',
       'type': 'none',
       'dependencies': [
         'ios_strings_gen',
         'ios_theme_resources_gen',
       ],
     },
     {
+      # GN version: //ios/chrome/app/strings
       'target_name': 'ios_strings_gen',
       'type': 'none',
       'hard_dependency': 1,
       'actions': [
         {
+          # GN version: //ios/chrome/app/strings:ios_locale_settings
           'action_name': 'generate_ios_locale_settings',
           'variables': {
             'grit_whitelist': '',
             'grit_grd_file': 'app/strings/ios_locale_settings.grd',
           },
           'includes': [ '../../build/grit_action.gypi' ],
         },
         {
+          # GN version: //ios/chrome/app/strings:ios_strings
           'action_name': 'generate_ios_strings',
           'variables': {
             'grit_whitelist': '',
             'grit_grd_file': 'app/strings/ios_strings.grd',
           },
           'includes': [ '../../build/grit_action.gypi' ],
         },
         {
+          # GN version: //ios/chrome/app/strings:ios_chromium_strings
           'action_name': 'generate_ios_chromium_strings',
           'variables': {
             'grit_whitelist': '',
             'grit_grd_file': 'app/strings/ios_chromium_strings.grd',
           },
           'includes': [ '../../build/grit_action.gypi' ],
         },
         {
+          # GN version: //ios/chrome/app/strings:ios_google_chrome_strings
           'action_name': 'generate_ios_google_chrome_strings',
           'variables': {
             'grit_whitelist': '',
             'grit_grd_file': 'app/strings/ios_google_chrome_strings.grd',
           },
           'includes': [ '../../build/grit_action.gypi' ],
         },
       ],
       'includes': [ '../../build/grit_target.gypi' ],
       # Override the exported include-dirs; ios/chrome/grit/ios_*strings.h
       # should only be referenceable as ios/chrome/grit to allow DEPS-time
       # checking of usage.
       'direct_dependent_settings': {
         'include_dirs': [
           '<(grit_base_dir)',
         ],
         'include_dirs!': [
           '<(grit_out_dir)',
         ],
       }
     },
     {
+      # GN version: //ios/chrome/app/theme
       'target_name': 'ios_theme_resources_gen',
       'type': 'none',
       'hard_dependency': 1,
       'actions': [
         {
           'action_name': 'ios_theme_resources',
           'variables': {
             'grit_whitelist': '',
             'grit_grd_file': 'app/theme/ios_theme_resources.grd',
           },
@@ skipping 143 matching lines @@
         '../../components/components.gyp:variations_service',
         'ios_chrome_ui_string_overrider_factory_gen',
       ],
       'sources': [
         '<(SHARED_INTERMEDIATE_DIR)/<(ui_string_overrider_output_basename).cc',
         '<(SHARED_INTERMEDIATE_DIR)/<(ui_string_overrider_output_basename).h',
       ],
     },
   ],
 }