Enable ash shell and unit tests in GN build.

ui/views_content_client/views_content_client.gyp

 # 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.
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
+      # GN version: //ui/views_content_client
       'target_name': 'views_content_client',
       'type': '<(component)',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../base/base.gyp:base_i18n',
         '../../content/content.gyp:content',
         '../../content/content_shell_and_tests.gyp:content_shell_lib',
         '../../third_party/icu/icu.gyp:icui18n',
         '../../third_party/icu/icu.gyp:icuuc',
         '../base/ui_base.gyp:ui_base',
         '../events/events.gyp:events',
         '../gfx/gfx.gyp:gfx',
         '../gfx/gfx.gyp:gfx_geometry',
         '../resources/ui_resources.gyp:ui_resources',
         '../resources/ui_resources.gyp:ui_test_pak',
         '../views/views.gyp:views',
         '../views/views.gyp:views_test_support',
       ],
       'defines': [
         'VIEWS_CONTENT_CLIENT_IMPLEMENTATION',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'views_content_browser_client.cc',
         'views_content_browser_client.h',
         'views_content_client.cc',
         'views_content_client.h',
         'views_content_client_export.h',
         'views_content_client_main_parts.cc',
         'views_content_client_main_parts.h',
         'views_content_client_main_parts_aura.cc',
         'views_content_client_main_parts_aura.h',
         'views_content_client_main_parts_chromeos.cc',
         'views_content_client_main_parts_desktop_aura.cc',
         'views_content_client_main_parts_mac.mm',
         'views_content_main_delegate.cc',
       ],
       'conditions': [
         ['use_aura==1', {
           'dependencies': [
             '../aura/aura.gyp:aura',
           ],
         }],  # use_aura==1
         ['chromeos==1', {
           'sources!': [
             'views_content_client_main_parts_desktop_aura.cc',
           ]
         }],  # chromeos==1
       ],
     },  # target_name: views_content_client
   ],
 }