Move Singleton and related structs to namespace base

extensions/browser/image_loader_factory.cc

 // Copyright 2014 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 "extensions/browser/image_loader_factory.h"
 
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/browser/image_loader.h"
 
 namespace extensions {
 
 // static
 ImageLoader* ImageLoaderFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<ImageLoader*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 ImageLoaderFactory* ImageLoaderFactory::GetInstance() {
-  return Singleton<ImageLoaderFactory>::get();
+  return base::Singleton<ImageLoaderFactory>::get();
 }
 
 ImageLoaderFactory::ImageLoaderFactory()
     : BrowserContextKeyedServiceFactory(
         "ImageLoader",
         BrowserContextDependencyManager::GetInstance()) {
 }
 
 ImageLoaderFactory::~ImageLoaderFactory() {
 }
 
 KeyedService* ImageLoaderFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   return new ImageLoader;
 }
 
 bool ImageLoaderFactory::ServiceIsCreatedWithBrowserContext() const {
   return false;
 }
 
 content::BrowserContext* ImageLoaderFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   return ExtensionsBrowserClient::Get()->GetOriginalContext(context);
 }
 
 }  // namespace extensions