cros: Preload and reuse the lock screen across lock sessions

chrome/browser/chromeos/login/session/chrome_session_manager.cc

 // 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.
 
 #include "chrome/browser/chromeos/login/session/chrome_session_manager.h"
 
 #include <memory>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/sys_info.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part_chromeos.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/app_mode/arc/arc_kiosk_app_manager.h"
 #include "chrome/browser/chromeos/app_mode/kiosk_app_launch_error.h"
 #include "chrome/browser/chromeos/app_mode/kiosk_app_manager.h"
 #include "chrome/browser/chromeos/arc/arc_service_launcher.h"
 #include "chrome/browser/chromeos/boot_times_recorder.h"
+#include "chrome/browser/chromeos/idle_detector.h"
+#include "chrome/browser/chromeos/login/lock/webui_screen_locker.h"
 #include "chrome/browser/chromeos/login/login_wizard.h"
 #include "chrome/browser/chromeos/login/session/user_session_manager.h"
 #include "chrome/browser/chromeos/login/wizard_controller.h"
 #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/ash/ash_util.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/prefs/pref_service.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/user_manager/user_manager.h"
 #include "components/user_manager/user_names.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/common/content_switches.h"
 
 namespace chromeos {
 
 namespace {
 
+// Duration of user inactivity before preloading the lock screen.
+const int IDLE_SECONDS_BEFORE_PRELOADING_LOCK_SCREEN = 8;

[xiyuan, 2016/12/09 22:59:55]

const -> constexpr

IDLE_SECONDS_BEFORE_PRELOADING_LOCK_SCREEN ->
kIdelSecondsBeforePreloadingLockScreen

[jdufault, 2016/12/12 20:08:27]

Done.

+
 // Whether kiosk auto launch should be started.
 bool ShouldAutoLaunchKioskApp(const base::CommandLine& command_line) {
   KioskAppManager* app_manager = KioskAppManager::Get();
   return command_line.HasSwitch(switches::kLoginManager) &&
          !command_line.HasSwitch(switches::kForceLoginManagerInTests) &&
          app_manager->IsAutoLaunchEnabled() &&
          KioskAppLaunchError::Get() == KioskAppLaunchError::NONE;
 }
 
 // Starts kiosk app auto launch and shows the splash screen.
@@ skipping 168 matching lines @@
   // Notifies UserManager so that it can update login state.
   user_manager::UserManager* user_manager = user_manager::UserManager::Get();
   if (user_manager)
     user_manager->OnSessionStarted();
 
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_SESSION_STARTED,
       content::Source<session_manager::SessionManager>(this),
       content::Details<const user_manager::User>(
           user_manager->GetActiveUser()));
+
+  if (chromeos::WebUIScreenLocker::ShouldShareLockScreen()) {
+    idle_detector_ = base::MakeUnique<chromeos::IdleDetector>(
+        base::Bind(&chromeos::WebUIScreenLocker::Preload));
+    idle_detector_->Start(base::TimeDelta::FromSeconds(
+        IDLE_SECONDS_BEFORE_PRELOADING_LOCK_SCREEN));
+  }
 }
 
 void ChromeSessionManager::NotifyUserLoggedIn(const AccountId& user_account_id,
                                               const std::string& user_id_hash,
                                               bool browser_restart) {
   BootTimesRecorder* btl = BootTimesRecorder::Get();
   btl->AddLoginTimeMarker("UserLoggedIn-Start", false);
   session_manager::SessionManager::NotifyUserLoggedIn(
       user_account_id, user_id_hash, browser_restart);
   btl->AddLoginTimeMarker("UserLoggedIn-End", false);
 }
 
 }  // namespace chromeos