Move Singleton and related structs to namespace base

chrome/browser/policy/cloud/user_policy_signin_service_factory.h

 // Copyright (c) 2012 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_POLICY_CLOUD_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_POLICY_CLOUD_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
@@ skipping 32 matching lines @@
       content::BrowserContext* profile) const override;
 
   // Overridden to cause this object to be created when the profile is created.
   bool ServiceIsCreatedWithBrowserContext() const override;
 
   // Register the preferences related to cloud-based user policy.
   void RegisterProfilePrefs(
       user_prefs::PrefRegistrySyncable* registry) override;
 
  private:
-  friend struct DefaultSingletonTraits<UserPolicySigninServiceFactory>;
+  friend struct base::DefaultSingletonTraits<UserPolicySigninServiceFactory>;
 
   UserPolicySigninServiceFactory();
   ~UserPolicySigninServiceFactory() override;
 
   DISALLOW_COPY_AND_ASSIGN(UserPolicySigninServiceFactory);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_CLOUD_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_