Screensaver at login screen.

chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.cc

+// Copyright (c) 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.
+
+#include "chrome/browser/chromeos/kiosk_mode/kiosk_mode_screensaver.h"
+
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "chrome/browser/chromeos/dbus/dbus_thread_manager.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/browser/chromeos/ui/screensaver_extension_dialog.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "content/public/browser/notification_service.h"
+
+namespace {
+
+// This (along with screensaver location) will change once we have the
+// retail mode enterprise policy set up.
+const int64 kScreensaverIdleTimeout = 60;
+
+}  // namespace
+
+namespace chromeos {
+
+KioskModeScreensaver::KioskModeScreensaver() {
+  // We should NOT be created if already logged in.
+  CHECK(!chromeos::UserManager::Get()->user_is_logged_in());
+
+  registrar_.Add(this, chrome::NOTIFICATION_LOGIN_USER_CHANGED,
+                 content::NotificationService::AllSources());
+
+  // We will register ourselves now and unregister if a user logs in.
+  chromeos::PowerManagerClient* power_manager =
+      chromeos::DBusThreadManager::Get()->GetPowerManagerClient();
+  if (!power_manager->HasObserver(this))
+    power_manager->AddObserver(this);
+
+  // Register for the next Idle for kScreensaverIdleTimeout event.
+  chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
+      RequestIdleNotification(kScreensaverIdleTimeout * 1000);
+}
+
+KioskModeScreensaver::~KioskModeScreensaver() {
+  chromeos::PowerManagerClient* power_manager =
+      chromeos::DBusThreadManager::Get()->GetPowerManagerClient();

[xiyuan, 2012/02/27 18:26:30]

When will this dtor be called? DBusThreadManager will be released when
BrowserMainLoop is gone. So if this is called after that, it might crash.

[rkc, 2012/02/27 22:24:43]

As discussed, made changes to add a shutdown function to the screensaver and
call it before DBusThreadManager shuts down.

Also added code to shutdown in case a user logs in, since we really won't need
to be around after that anyway.

+  if (power_manager->HasObserver(this))
+    power_manager->RemoveObserver(this);
+}
+
+// NotificationObserver overrides:
+void KioskModeScreensaver::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  DCHECK_EQ(type, chrome::NOTIFICATION_LOGIN_USER_CHANGED);
+  // User logged in, remove our observers, screensaver will be deactivated.
+  chromeos::PowerManagerClient* power_manager =
+      chromeos::DBusThreadManager::Get()->GetPowerManagerClient();
+  if (power_manager->HasObserver(this))
+    power_manager->RemoveObserver(this);
+}
+
+void KioskModeScreensaver::IdleNotify(int64 threshold) {
+  // We're idle, next time we go active, we need to know so we can remove
+  // the logout dialog if it's still up.
+  chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
+      RequestActiveNotification();
+
+  browser::ShowScreensaverDialog();
+}
+
+void KioskModeScreensaver::ActiveNotify() {
+  // Before anything else, close the logout dialog to prevent restart
+  browser::CloseScreensaverDialog();
+
+  // Now that we're active, register a request for notification for
+  // the next time we go idle for kScreensaverIdleTimeout seconds.
+  chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->
+      RequestIdleNotification(kScreensaverIdleTimeout * 1000);
+}
+
+static base::LazyInstance<KioskModeScreensaver>
+    g_kiosk_mode_login_observer = LAZY_INSTANCE_INITIALIZER;
+
+void InitKioskModeScreensaver() {
+  g_kiosk_mode_login_observer.Get();
+}
+
+}  // namespace chromeos