Move Singleton and related structs to namespace base

chrome/browser/web_data_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_WEB_DATA_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_WEB_DATA_SERVICE_FACTORY_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "components/keyed_service/core/service_access_type.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
+
 class KeywordWebDataService;
 class Profile;
 class TokenWebData;
 class WebDataServiceWrapper;
 
 #if defined(OS_WIN)
 class PasswordWebDataService;
 #endif
 
 namespace autofill {
@@ skipping 29 matching lines @@
 #if defined(OS_WIN)
   // Returns the PasswordWebDataService associated with the |profile|.
   static scoped_refptr<PasswordWebDataService> GetPasswordWebDataForProfile(
       Profile* profile,
       ServiceAccessType access_type);
 #endif
 
   static WebDataServiceFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<WebDataServiceFactory>;
+  friend struct base::DefaultSingletonTraits<WebDataServiceFactory>;
 
   WebDataServiceFactory();
   ~WebDataServiceFactory() override;
 
   // |BrowserContextKeyedBaseFactory| methods:
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const override;
   bool ServiceIsNULLWhileTesting() const override;
 
   DISALLOW_COPY_AND_ASSIGN(WebDataServiceFactory);
 };
 
 #endif  // CHROME_BROWSER_WEB_DATA_SERVICE_FACTORY_H_