Move Singleton and related structs to namespace base

chrome/browser/chromeos/extensions/users_private/users_private_delegate_factory.h

 // Copyright 2015 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_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_FACTORY_H__
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_FACTORY_H__
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
 namespace context {
 class BrowserContext;
 }
 
 namespace extensions {
 class UsersPrivateDelegate;
 
 // BrowserContextKeyedServiceFactory for each UsersPrivateDelegate.
 class UsersPrivateDelegateFactory : public BrowserContextKeyedServiceFactory {
  public:
   static UsersPrivateDelegate* GetForBrowserContext(
       content::BrowserContext* browser_context);
 
   static UsersPrivateDelegateFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<UsersPrivateDelegateFactory>;
+  friend struct base::DefaultSingletonTraits<UsersPrivateDelegateFactory>;
 
   UsersPrivateDelegateFactory();
   ~UsersPrivateDelegateFactory() override;
 
   // BrowserContextKeyedBaseFactory implementation.
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const override;
 
   DISALLOW_COPY_AND_ASSIGN(UsersPrivateDelegateFactory);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_FACTORY_H__