Move Singleton and related structs to namespace base

chrome/browser/chromeos/extensions/install_limiter_factory.h

 // Copyright (c) 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_CHROMEOS_EXTENSIONS_INSTALL_LIMITER_FACTORY_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_INSTALL_LIMITER_FACTORY_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
 class Profile;
 
 namespace extensions {
 
 class InstallLimiter;
 
 // Singleton that owns all InstallLimiter and associates them with profiles.
 class InstallLimiterFactory : public BrowserContextKeyedServiceFactory {
  public:
   static InstallLimiter* GetForProfile(Profile* profile);
 
   static InstallLimiterFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<InstallLimiterFactory>;
+  friend struct base::DefaultSingletonTraits<InstallLimiterFactory>;
 
   InstallLimiterFactory();
   ~InstallLimiterFactory() override;
 
   // BrowserContextKeyedServiceFactory overrides:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const override;
 
   DISALLOW_COPY_AND_ASSIGN(InstallLimiterFactory);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_INSTALL_LIMITER_FACTORY_H_