Move Singleton and related structs to namespace base

chrome/browser/chromeos/policy/user_network_configuration_updater_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_CHROMEOS_POLICY_USER_NETWORK_CONFIGURATION_UPDATER_FACTORY_H_
 #define CHROME_BROWSER_CHROMEOS_POLICY_USER_NETWORK_CONFIGURATION_UPDATER_FACTORY_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
+namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
-
+}  // namespace base
 class Profile;
 
 namespace policy {
 
 class UserNetworkConfigurationUpdater;
 
 // Factory to create UserNetworkConfigurationUpdater.
 class UserNetworkConfigurationUpdaterFactory
     : public BrowserContextKeyedServiceFactory {
  public:
   // Returns an existing or creates a new UserNetworkConfigurationUpdater for
   // |profile|. Will return NULL if this service isn't allowed for |profile|,
   // i.e. for all but the primary user's profile.
   static UserNetworkConfigurationUpdater* GetForProfile(Profile* profile);
 
   static UserNetworkConfigurationUpdaterFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<UserNetworkConfigurationUpdaterFactory>;
+  friend struct base::DefaultSingletonTraits<
+      UserNetworkConfigurationUpdaterFactory>;
 
   UserNetworkConfigurationUpdaterFactory();
   ~UserNetworkConfigurationUpdaterFactory() override;
 
   // BrowserContextKeyedServiceFactory:
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
   bool ServiceIsCreatedWithBrowserContext() const override;
   bool ServiceIsNULLWhileTesting() const override;
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
 
   DISALLOW_COPY_AND_ASSIGN(UserNetworkConfigurationUpdaterFactory);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_USER_NETWORK_CONFIGURATION_UPDATER_FACTORY_H_