UMA: How often are different network error screens encountered during OOBE

chrome/chrome_tests_unit.gypi

 # 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': {
     'chrome_unit_tests_sources': [
       '../apps/saved_files_service_unittest.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.h',
       '../components/autofill/content/renderer/test_password_generation_agent.cc',
@@ skipping 180 matching lines @@
       'browser/chromeos/input_method/input_method_configuration_unittest.cc',
       'browser/chromeos/input_method/input_method_engine_unittest.cc',
       'browser/chromeos/input_method/input_method_manager_impl_unittest.cc',
       'browser/chromeos/input_method/input_method_persistence_unittest.cc',
       'browser/chromeos/input_method/input_method_util_unittest.cc',
       'browser/chromeos/kiosk_mode/kiosk_mode_idle_logout_unittest.cc',
       'browser/chromeos/kiosk_mode/kiosk_mode_settings_unittest.cc',
       'browser/chromeos/locale_change_guard_unittest.cc',
       'browser/chromeos/login/auth/cryptohome_authenticator_unittest.cc',
       'browser/chromeos/login/auth/online_attempt_unittest.cc',
+      'browser/chromeos/login/error_screens_histogram_helper_unittest.cc',
       'browser/chromeos/login/existing_user_controller_auto_login_unittest.cc',
       'browser/chromeos/login/hwid_checker_unittest.cc',
       'browser/chromeos/login/profile_auth_data_unittest.cc',
       'browser/chromeos/login/saml/saml_offline_signin_limiter_unittest.cc',
       'browser/chromeos/login/screens/screen_context_unittest.cc',
       'browser/chromeos/login/signin/merge_session_load_page_unittest.cc',
       'browser/chromeos/login/supervised/supervised_user_authentication_unittest.cc',
       'browser/chromeos/login/users/multi_profile_user_controller_unittest.cc',
       'browser/chromeos/login/users/user_manager_unittest.cc',
       'browser/chromeos/login/users/wallpaper/wallpaper_manager_unittest.cc',
@@ skipping 2662 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }