Move Singleton and related structs to namespace base

chrome/browser/favicon/fallback_icon_service_factory.cc

 // Copyright 2015 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/favicon/fallback_icon_service_factory.h"
 
 #include "base/memory/singleton.h"
 #include "chrome/browser/favicon/chrome_fallback_icon_client_factory.h"
 #include "components/favicon/core/fallback_icon_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "content/public/browser/browser_context.h"
 
 // static
 favicon::FallbackIconService* FallbackIconServiceFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<favicon::FallbackIconService*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 // static
 FallbackIconServiceFactory* FallbackIconServiceFactory::GetInstance() {
-  return Singleton<FallbackIconServiceFactory>::get();
+  return base::Singleton<FallbackIconServiceFactory>::get();
 }
 
 FallbackIconServiceFactory::FallbackIconServiceFactory()
     : BrowserContextKeyedServiceFactory(
         "FallbackIconService",
         BrowserContextDependencyManager::GetInstance()) {
   DependsOn(ChromeFallbackIconClientFactory::GetInstance());
 }
 
 FallbackIconServiceFactory::~FallbackIconServiceFactory() {}
 
 KeyedService* FallbackIconServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   favicon::FallbackIconClient* fallback_icon_client =
       ChromeFallbackIconClientFactory::GetForBrowserContext(context);
   return new favicon::FallbackIconService(fallback_icon_client);
 }
 
 bool FallbackIconServiceFactory::ServiceIsNULLWhileTesting() const {
   return true;
 }