Remove NOTIFICATION_SYSTEM_SETTING_CHANGED, switch CrosSettings to base::CallbackRegistry.

chrome/browser/chromeos/app_mode/kiosk_app_manager.cc

Index: chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
diff --git a/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc b/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
index c9e4ef8c9a2a698cc2b99f2b39b0143d0d658bb6..4e3bcebc2ccc3394a3652833c5fb88bf05dbac77 100644
--- a/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
+++ b/chrome/browser/chromeos/app_mode/kiosk_app_manager.cc
@@ -314,19 +314,21 @@ void KioskAppManager::RemoveObserver(KioskAppManagerObserver* observer) {
 
 KioskAppManager::KioskAppManager() : ownership_established_(false) {
   UpdateAppData();
-  CrosSettings::Get()->AddSettingsObserver(
-      kAccountsPrefDeviceLocalAccounts, this);
-  CrosSettings::Get()->AddSettingsObserver(
-      kAccountsPrefDeviceLocalAccountAutoLoginId, this);
+  local_accounts_subscription_ =
+      CrosSettings::Get()->AddSettingsObserver(
+          kAccountsPrefDeviceLocalAccounts,
+          base::Bind(&KioskAppManager::UpdateAppData, base::Unretained(this)));
+  local_account_auto_login_id_subscription_ =
+      CrosSettings::Get()->AddSettingsObserver(
+          kAccountsPrefDeviceLocalAccountAutoLoginId,
+          base::Bind(&KioskAppManager::UpdateAppData, base::Unretained(this)));
 }
 
 KioskAppManager::~KioskAppManager() {}
 
 void KioskAppManager::CleanUp() {
-  CrosSettings::Get()->RemoveSettingsObserver(
-      kAccountsPrefDeviceLocalAccounts, this);
-  CrosSettings::Get()->RemoveSettingsObserver(
-      kAccountsPrefDeviceLocalAccountAutoLoginId, this);
+  local_accounts_subscription_.reset();
+  local_account_auto_login_id_subscription_.reset();
   apps_.clear();
 }
 
@@ -394,13 +396,6 @@ void KioskAppManager::UpdateAppData() {
                     OnKioskAppsSettingsChanged());
 }
 
-void KioskAppManager::Observe(int type,
-                              const content::NotificationSource& source,
-                              const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_SYSTEM_SETTING_CHANGED, type);
-  UpdateAppData();
-}
-
 void KioskAppManager::GetKioskAppIconCacheDir(base::FilePath* cache_dir) {
   base::FilePath user_data_dir;
   CHECK(PathService::Get(chrome::DIR_USER_DATA, &user_data_dir));