Move Singleton and related structs to namespace base

chrome/browser/extensions/install_tracker_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/extensions/install_tracker_factory.h"
 
 #include "base/memory/singleton.h"
 #include "chrome/browser/extensions/install_tracker.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_prefs_factory.h"
 #include "extensions/browser/extension_system_provider.h"
 #include "extensions/browser/extensions_browser_client.h"
 
 namespace extensions {
 
 // static
 InstallTracker* InstallTrackerFactory::GetForBrowserContext(
     content::BrowserContext* context) {
   return static_cast<InstallTracker*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 InstallTrackerFactory* InstallTrackerFactory::GetInstance() {
-  return Singleton<InstallTrackerFactory>::get();
+  return base::Singleton<InstallTrackerFactory>::get();
 }
 
 InstallTrackerFactory::InstallTrackerFactory()
     : BrowserContextKeyedServiceFactory(
         "InstallTracker",
         BrowserContextDependencyManager::GetInstance()) {
   DependsOn(ExtensionsBrowserClient::Get()->GetExtensionSystemFactory());
   DependsOn(ExtensionPrefsFactory::GetInstance());
 }
 
 InstallTrackerFactory::~InstallTrackerFactory() {
 }
 
 KeyedService* InstallTrackerFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   return new InstallTracker(context, ExtensionPrefs::Get(context));
 }
 
 content::BrowserContext* InstallTrackerFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   // The installs themselves are routed to the non-incognito profile and so
   // should the install progress.
   return ExtensionsBrowserClient::Get()->GetOriginalContext(context);
 }
 
 }  // namespace extensions