Move Singleton and related structs to namespace base

chrome/browser/precache/precache_manager_factory.h

 // 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.
 
 #ifndef CHROME_BROWSER_PRECACHE_PRECACHE_MANAGER_FACTORY_H_
 #define CHROME_BROWSER_PRECACHE_PRECACHE_MANAGER_FACTORY_H_
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace precache {
 
 class PrecacheManager;
 
 class PrecacheManagerFactory : public BrowserContextKeyedServiceFactory {
  public:
   static PrecacheManager* GetForBrowserContext(
       content::BrowserContext* browser_context);
   static PrecacheManagerFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<PrecacheManagerFactory>;
+  friend struct base::DefaultSingletonTraits<PrecacheManagerFactory>;
 
   PrecacheManagerFactory();
   ~PrecacheManagerFactory() override;
 
   // BrowserContextKeyedServiceFactory:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* browser_context) const override;
 
   DISALLOW_COPY_AND_ASSIGN(PrecacheManagerFactory);
 };
 
 }  // namespace precache
 
 #endif  // CHROME_BROWSER_PRECACHE_PRECACHE_MANAGER_FACTORY_H_