The chrome.screenlockPrivate API allows select apps to control the ChromeOS ScreenLocker.

chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/profiles/chrome_browser_main_extra_parts_profiles.h"
 
 #include "apps/app_keep_alive_service_factory.h"
 #include "apps/app_load_service_factory.h"
 #include "apps/app_restore_service_factory.h"
 #include "apps/shell_window_geometry_cache.h"
@@ skipping 119 matching lines @@
 #endif
 
 #if defined(ENABLE_MANAGED_USERS)
 #include "chrome/browser/managed_mode/managed_user_service_factory.h"
 #include "chrome/browser/managed_mode/managed_user_sync_service_factory.h"
 #endif
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/extensions/input_method_api.h"
 #include "chrome/browser/chromeos/extensions/media_player_api.h"
+#include "chrome/browser/chromeos/extensions/screenlock_private_api.h"
 #include "chrome/browser/extensions/api/input_ime/input_ime_api.h"
 #include "chrome/browser/extensions/api/networking_private/networking_private_event_router_factory.h"
 #if defined(FILE_MANAGER_EXTENSION)
 #include "chrome/browser/chromeos/extensions/file_manager/file_browser_private_api_factory.h"
 #endif
 #endif
 
 #if defined(USE_AURA)
 #include "chrome/browser/ui/gesture_prefs_observer_factory_aura.h"
 #endif
@@ skipping 110 matching lines @@
   extensions::HistoryAPI::GetFactoryInstance();
   extensions::IdentityAPI::GetFactoryInstance();
   extensions::IdleManagerFactory::GetInstance();
   extensions::InstallTrackerFactory::GetInstance();
 #if defined(TOOLKIT_VIEWS)
   extensions::InputAPI::GetFactoryInstance();
 #endif
 #if defined(OS_CHROMEOS)
   extensions::InputImeAPI::GetFactoryInstance();
   extensions::InputMethodAPI::GetFactoryInstance();
+  extensions::ScreenlockPrivateEventRouter::GetFactoryInstance();
 #endif
   extensions::LocationManager::GetFactoryInstance();
   extensions::ManagementAPI::GetFactoryInstance();
   extensions::MDnsAPI::GetFactoryInstance();
   extensions::MediaGalleriesPrivateAPI::GetFactoryInstance();
 #if defined(OS_CHROMEOS)
   extensions::MediaPlayerAPI::GetFactoryInstance();
 #endif
   extensions::MenuManagerFactory::GetInstance();
   extensions::OmniboxAPI::GetFactoryInstance();
@@ skipping 93 matching lines @@
 #if defined(ENABLE_EXTENSIONS)
   TokenCacheServiceFactory::GetInstance();
 #endif
   TokenServiceFactory::GetInstance();
   WebDataServiceFactory::GetInstance();
 }
 
 void ChromeBrowserMainExtraPartsProfiles::PreProfileInit() {
   EnsureBrowserContextKeyedServiceFactoriesBuilt();
 }