Identity API: Add chrome.identity.onSignInChanged routing and IDL

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.
 {
   'targets': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 791 matching lines @@
         'browser/extensions/api/dial/dial_device_data_unittest.cc',
         'browser/extensions/api/dial/dial_registry_unittest.cc',
         'browser/extensions/api/dial/dial_service_unittest.cc',
         'browser/extensions/api/discovery/discovery_api_unittest.cc',
         'browser/extensions/api/enterprise_platform_keys_private/enterprise_platform_keys_private_api_unittest.cc',
         'browser/extensions/api/extension_action/extension_action_prefs_unittest.cc',
         'browser/extensions/api/extension_action/extension_browser_actions_api_unittest.cc',
         'browser/extensions/api/file_system/file_system_api_unittest.cc',
         'browser/extensions/api/identity/experimental_web_auth_flow_unittest.cc',
         'browser/extensions/api/identity/gaia_web_auth_flow_unittest.cc',
+        'browser/extensions/api/identity/identity_event_router_unittest.cc',
         'browser/extensions/api/identity/identity_mint_queue_unittest.cc',
         'browser/extensions/api/idle/idle_api_unittest.cc',
         'browser/extensions/api/log_private/syslog_parser_unittest.cc',
         'browser/extensions/api/messaging/native_message_process_host_unittest.cc',
         'browser/extensions/api/messaging/native_messaging_host_manifest_unittest.cc',
         'browser/extensions/api/mdns/dns_sd_registry_unittest.cc',
         'browser/extensions/api/networking_private/networking_private_crypto_unittest.cc',
         'browser/extensions/api/omnibox/omnibox_unittest.cc',
         'browser/extensions/api/permissions/permissions_api_helpers_unittest.cc',
         'browser/extensions/api/power/power_api_unittest.cc',
@@ skipping 2019 matching lines @@
             'browser/ui/app_list/test/fake_profile.h',
             'browser/ui/app_list/test/fake_profile_store.cc',
             'browser/ui/app_list/test/fake_profile_store.h',
             'browser/ui/app_list/test/fast_show_pickler_unittest.cc',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }