Move Singleton and related structs to namespace base

chrome/browser/signin/chrome_signin_client_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 "chrome/browser/signin/chrome_signin_client_factory.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/signin/signin_error_controller_factory.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
 ChromeSigninClientFactory::ChromeSigninClientFactory()
     : BrowserContextKeyedServiceFactory(
           "ChromeSigninClient",
           BrowserContextDependencyManager::GetInstance()) {
   DependsOn(SigninErrorControllerFactory::GetInstance());
 }
 
 ChromeSigninClientFactory::~ChromeSigninClientFactory() {}
 
 // static
 SigninClient* ChromeSigninClientFactory::GetForProfile(Profile* profile) {
   return static_cast<SigninClient*>(
       GetInstance()->GetServiceForBrowserContext(profile, true));
 }
 
 // static
 ChromeSigninClientFactory* ChromeSigninClientFactory::GetInstance() {
-  return Singleton<ChromeSigninClientFactory>::get();
+  return base::Singleton<ChromeSigninClientFactory>::get();
 }
 
 KeyedService* ChromeSigninClientFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = static_cast<Profile*>(context);
   ChromeSigninClient* client = new ChromeSigninClient(
       profile, SigninErrorControllerFactory::GetForProfile(profile));
   return client;
 }