Remove NOTIFICATION_SYSTEM_SETTING_CHANGED, switch CrosSettings to base::CallbackRegistry.

chrome/browser/chromeos/login/existing_user_controller_auto_login_unittest.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 <string>
 
 #include "base/message_loop/message_loop.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/login/existing_user_controller.h"
 #include "chrome/browser/chromeos/login/mock_login_display.h"
@@ skipping 69 matching lines @@
         kAccountsPrefDeviceLocalAccountsKeyId,
         kAutoLoginAccountId);
     account->SetIntegerWithoutPathExpansion(
         kAccountsPrefDeviceLocalAccountsKeyType,
         policy::DeviceLocalAccount::TYPE_PUBLIC_SESSION);
     base::ListValue accounts;
     accounts.Append(account.release());
     CrosSettings::Get()->Set(kAccountsPrefDeviceLocalAccounts, accounts);
 
     // Prevent settings changes from auto-starting the timer.
-    CrosSettings::Get()->RemoveSettingsObserver(
-        kAccountsPrefDeviceLocalAccountAutoLoginId,
-        existing_user_controller());
-    CrosSettings::Get()->RemoveSettingsObserver(
-        kAccountsPrefDeviceLocalAccountAutoLoginDelay,
-        existing_user_controller());
+    existing_user_controller_->
+        local_account_auto_login_id_subscription_.reset();
+    existing_user_controller_->
+        local_account_auto_login_delay_subscription_.reset();
   }
 
   const ExistingUserController* existing_user_controller() const {
     return ExistingUserController::current_controller();
   }
 
   ExistingUserController* existing_user_controller() {
     return ExistingUserController::current_controller();
   }
 
@@ skipping 174 matching lines @@
   ConfigureAutoLogin();
   ASSERT_TRUE(auto_login_timer());
   EXPECT_FALSE(auto_login_timer()->IsRunning());
   EXPECT_EQ(auto_login_timer()->GetCurrentDelay().InMilliseconds(),
             kAutoLoginDelay2);
   EXPECT_EQ(auto_login_username(), "");
   EXPECT_EQ(auto_login_delay(), kAutoLoginDelay2);
 }
 
 }  // namespace chromeos