Move Singleton and related structs to namespace base

chrome/browser/push_messaging/push_messaging_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/push_messaging/push_messaging_service_factory.h"
 
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/push_messaging/push_messaging_service_impl.h"
 #include "chrome/browser/services/gcm/fake_gcm_profile_service.h"
 #include "chrome/browser/services/gcm/gcm_profile_service_factory.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 
 // static
 PushMessagingServiceImpl* PushMessagingServiceFactory::GetForProfile(
     content::BrowserContext* profile) {
   // The Push API is not currently supported in incognito mode.
   // See https://crbug.com/401439.
   if (profile->IsOffTheRecord())
     return NULL;
 
   return static_cast<PushMessagingServiceImpl*>(
       GetInstance()->GetServiceForBrowserContext(profile, true));
 }
 
 // static
 PushMessagingServiceFactory* PushMessagingServiceFactory::GetInstance() {
-  return Singleton<PushMessagingServiceFactory>::get();
+  return base::Singleton<PushMessagingServiceFactory>::get();
 }
 
 PushMessagingServiceFactory::PushMessagingServiceFactory()
     : BrowserContextKeyedServiceFactory(
           "PushMessagingProfileService",
           BrowserContextDependencyManager::GetInstance()) {
   DependsOn(gcm::GCMProfileServiceFactory::GetInstance());
 }
 
 PushMessagingServiceFactory::~PushMessagingServiceFactory() {
 }
 
 KeyedService* PushMessagingServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
   Profile* profile = Profile::FromBrowserContext(context);
   CHECK(!profile->IsOffTheRecord());
   return new PushMessagingServiceImpl(profile);
 }
 
 content::BrowserContext* PushMessagingServiceFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   return chrome::GetBrowserContextOwnInstanceInIncognito(context);
 }