Move Singleton and related structs to namespace base

chrome/browser/signin/easy_unlock_service_factory.h

 // Copyright 2014 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_EASY_UNLOCK_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_FACTORY_H_
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
 namespace content {
 class BrowserContext;
 }
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
+
 class EasyUnlockService;
 class Profile;
 
 // Singleton factory that builds and owns all EasyUnlockService.
 class EasyUnlockServiceFactory : public BrowserContextKeyedServiceFactory {
  public:
   static EasyUnlockServiceFactory* GetInstance();
 
   static EasyUnlockService* GetForBrowserContext(
       content::BrowserContext* browser_context);
 
   void set_app_path_for_testing(const base::FilePath& app_path) {
     app_path_for_testing_ = app_path;
   }
 
  private:
-  friend struct DefaultSingletonTraits<EasyUnlockServiceFactory>;
+  friend struct base::DefaultSingletonTraits<EasyUnlockServiceFactory>;
 
   EasyUnlockServiceFactory();
   ~EasyUnlockServiceFactory() override;
 
   // BrowserContextKeyedServiceFactory:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
   bool ServiceIsCreatedWithBrowserContext() const override;
   bool ServiceIsNULLWhileTesting() const override;
 
   base::FilePath app_path_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(EasyUnlockServiceFactory);
 };
 
 #endif  // CHROME_BROWSER_SIGNIN_EASY_UNLOCK_SERVICE_FACTORY_H_