Move Singleton and related structs to namespace base

chrome/browser/thumbnails/thumbnail_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/thumbnails/thumbnail_service_factory.h"
 
 #include "base/logging.h"
 #include "chrome/browser/history/top_sites_factory.h"
 #include "chrome/browser/thumbnails/thumbnail_service.h"
 #include "chrome/browser/thumbnails/thumbnail_service_impl.h"
@@ skipping 14 matching lines @@
 
 // static
 scoped_refptr<ThumbnailService> ThumbnailServiceFactory::GetForProfile(
     Profile* profile) {
   return static_cast<ThumbnailService*>(
       GetInstance()->GetServiceForBrowserContext(profile, true).get());
 }
 
 // static
 ThumbnailServiceFactory* ThumbnailServiceFactory::GetInstance() {
-  return Singleton<ThumbnailServiceFactory>::get();
+  return base::Singleton<ThumbnailServiceFactory>::get();
 }
 
 scoped_refptr<RefcountedKeyedService>
 ThumbnailServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   return scoped_refptr<RefcountedKeyedService>(
       new ThumbnailServiceImpl(static_cast<Profile*>(profile)));
 }