Move Singleton and related structs to namespace base

chrome/browser/chromeos/launcher_search_provider/launcher_search_provider_service_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_LAUNCHER_SEARCH_PROVIDER_LAUNCHER_SEARCH_PROVIDER_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_CHROMEOS_LAUNCHER_SEARCH_PROVIDER_LAUNCHER_SEARCH_PROVIDER_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "content/public/browser/browser_context.h"
 
 namespace chromeos {
 namespace launcher_search_provider {
 
 class Service;
 
 // Creates services per profile.
 class ServiceFactory : public BrowserContextKeyedServiceFactory {
  public:
   // Returns a service instance singleton, after creating it (if necessary).
   static Service* Get(content::BrowserContext* context);
 
   // Gets a singleton instance of the factory.
   static ServiceFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<ServiceFactory>;
+  friend struct base::DefaultSingletonTraits<ServiceFactory>;
 
   ServiceFactory();
   ~ServiceFactory() override;
 
   // BrowserContextKeyedServiceFactory overrides:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const override;
   bool ServiceIsCreatedWithBrowserContext() const override;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceFactory);
 };
 
 }  // namespace launcher_search_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LAUNCHER_SEARCH_PROVIDER_LAUNCHER_SEARCH_PROVIDER_SERVICE_FACTORY_H_