Move Singleton and related structs to namespace base

chrome/browser/background/background_contents_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/background/background_contents_service_factory.h"
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/background/background_contents_service.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "extensions/browser/extension_registry_factory.h"
 
 // static
 BackgroundContentsService* BackgroundContentsServiceFactory::GetForProfile(
     Profile* profile) {
   return static_cast<BackgroundContentsService*>(
       GetInstance()->GetServiceForBrowserContext(profile, true));
 }
 
 // static
 BackgroundContentsServiceFactory* BackgroundContentsServiceFactory::
     GetInstance() {
-  return Singleton<BackgroundContentsServiceFactory>::get();
+  return base::Singleton<BackgroundContentsServiceFactory>::get();
 }
 
 BackgroundContentsServiceFactory::BackgroundContentsServiceFactory()
     : BrowserContextKeyedServiceFactory(
         "BackgroundContentsService",
         BrowserContextDependencyManager::GetInstance()) {
   DependsOn(extensions::ExtensionRegistryFactory::GetInstance());
 }
 
 BackgroundContentsServiceFactory::~BackgroundContentsServiceFactory() {
@@ skipping 17 matching lines @@
 }
 
 bool
 BackgroundContentsServiceFactory::ServiceIsCreatedWithBrowserContext() const {
   return true;
 }
 
 bool BackgroundContentsServiceFactory::ServiceIsNULLWhileTesting() const {
   return true;
 }