Observe chrome::NOTIFICATION_APP_TERMINATING in Chrome's AppListViewDelegate

chrome/browser/signin/signin_manager_factory.h

 // 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.
 
 #ifndef CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 #define CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
@@ skipping 58 matching lines @@
   // |BuildServiceInstanceFor()|.
   void NotifyObserversOfSigninManagerCreationForTesting(
       SigninManagerBase* manager);
 
  private:
   friend struct DefaultSingletonTraits<SigninManagerFactory>;
 
   SigninManagerFactory();
   virtual ~SigninManagerFactory();
 
-#if defined(OS_MACOSX)
-  // List of observers. Does not check that list is empty on destruction, as
-  // there are some leaky singletons that observe the SigninManagerFactory.
-  mutable ObserverList<Observer> observer_list_;
-#else
   // List of observers. Checks that list is empty on destruction.
   mutable ObserverList<Observer, true> observer_list_;
-#endif
 
   // BrowserContextKeyedServiceFactory:
   virtual KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const OVERRIDE;
   virtual void BrowserContextShutdown(content::BrowserContext* context)
       OVERRIDE;
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_SIGNIN_MANAGER_FACTORY_H_