Move Singleton and related structs to namespace base

chrome/browser/search/hotword_service_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_SEARCH_HOTWORD_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
@@ skipping 23 matching lines @@
 
   // This will kick off the monitor that calls OnUpdateAudioDevices when the
   // number of audio devices changes (or is initialized). It needs to be a
   // separate function so it can be called after the service is initialized
   // (i.e., after startup). The monitor can't be initialized during startup
   // because it would slow down startup too much so it is delayed and not
   // called until it's needed by the webui in browser_options_handler.
   void UpdateMicrophoneState();
 
  private:
-  friend struct DefaultSingletonTraits<HotwordServiceFactory>;
+  friend struct base::DefaultSingletonTraits<HotwordServiceFactory>;
 
   HotwordServiceFactory();
   ~HotwordServiceFactory() override;
 
   // Overrides from BrowserContextKeyedServiceFactory:
   void RegisterProfilePrefs(
       user_prefs::PrefRegistrySyncable* registry) override;
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
 
   DISALLOW_COPY_AND_ASSIGN(HotwordServiceFactory);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_HOTWORD_SERVICE_FACTORY_H_