Move Singleton and related structs to namespace base

chrome/browser/bookmarks/startup_task_runner_service_factory.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/bookmarks/startup_task_runner_service_factory.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "components/bookmarks/browser/startup_task_runner_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
@@ skipping 10 matching lines @@
 // static
 StartupTaskRunnerService* StartupTaskRunnerServiceFactory::GetForProfile(
     Profile* profile) {
   return static_cast<StartupTaskRunnerService*>(
       GetInstance()->GetServiceForBrowserContext(profile, true));
 }
 
 // static
 StartupTaskRunnerServiceFactory*
     StartupTaskRunnerServiceFactory::GetInstance() {
-  return Singleton<StartupTaskRunnerServiceFactory>::get();
+  return base::Singleton<StartupTaskRunnerServiceFactory>::get();
 }
 
 KeyedService* StartupTaskRunnerServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
   return new StartupTaskRunnerService(profile->GetIOTaskRunner());
 }