Move Singleton and related structs to namespace base

ios/chrome/browser/sync/sync_setup_service_factory.cc

 // Copyright 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 "ios/chrome/browser/sync/sync_setup_service_factory.h"
 
 #include "base/memory/singleton.h"
 #include "components/keyed_service/ios/browser_state_dependency_manager.h"
 #include "ios/chrome/browser/sync/sync_setup_service.h"
 #include "ios/public/provider/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/public/provider/chrome/browser/keyed_service_provider.h"
 
 // static
 SyncSetupService* SyncSetupServiceFactory::GetForBrowserState(
     ios::ChromeBrowserState* browser_state) {
   return static_cast<SyncSetupService*>(
       GetInstance()->GetServiceForBrowserState(browser_state, true));
 }
 
 // static
 SyncSetupService* SyncSetupServiceFactory::GetForBrowserStateIfExists(
     ios::ChromeBrowserState* browser_state) {
   return static_cast<SyncSetupService*>(
       GetInstance()->GetServiceForBrowserState(browser_state, false));
 }
 
 // static
 SyncSetupServiceFactory* SyncSetupServiceFactory::GetInstance() {
-  return Singleton<SyncSetupServiceFactory>::get();
+  return base::Singleton<SyncSetupServiceFactory>::get();
 }
 
 SyncSetupServiceFactory::SyncSetupServiceFactory()
     : BrowserStateKeyedServiceFactory(
           "SyncSetupService",
           BrowserStateDependencyManager::GetInstance()) {
   DependsOn(ios::GetKeyedServiceProvider()->GetSyncServiceFactory());
 }
 
 SyncSetupServiceFactory::~SyncSetupServiceFactory() {
 }
 
 scoped_ptr<KeyedService> SyncSetupServiceFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
   ios::ChromeBrowserState* browser_state =
       ios::ChromeBrowserState::FromBrowserState(context);
   return make_scoped_ptr(new SyncSetupService(
       ios::GetKeyedServiceProvider()->GetSyncServiceForBrowserState(
           browser_state),
       browser_state->GetPrefs()));
 }