Move Singleton and related structs to namespace base

chrome/browser/download/download_service_factory.cc

 // 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.
 
 #include "chrome/browser/download/download_service_factory.h"
 
 #include "chrome/browser/download/download_service_impl.h"
 #include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
 // static
 DownloadService* DownloadServiceFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<DownloadService*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 // static
 DownloadServiceFactory* DownloadServiceFactory::GetInstance() {
-  return Singleton<DownloadServiceFactory>::get();
+  return base::Singleton<DownloadServiceFactory>::get();
 }
 
 DownloadServiceFactory::DownloadServiceFactory()
     : BrowserContextKeyedServiceFactory(
         "DownloadService",
         BrowserContextDependencyManager::GetInstance()) {
   DependsOn(HistoryServiceFactory::GetInstance());
 }
 
 DownloadServiceFactory::~DownloadServiceFactory() {
 }
 
 KeyedService* DownloadServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   DownloadService* service =
       new DownloadServiceImpl(static_cast<Profile*>(profile));
 
   // No need for initialization; initialization can be done on first
   // use of service.
 
   return service;
 }
 
 content::BrowserContext* DownloadServiceFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   return chrome::GetBrowserContextOwnInstanceInIncognito(context);
 }