Move Singleton and related structs to namespace base

chrome/browser/notifications/platform_notification_service_impl.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/notifications/platform_notification_service_impl.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 58 matching lines @@
 void CancelNotification(const std::string& id, ProfileID profile_id) {
   PlatformNotificationServiceImpl::GetInstance()
       ->GetNotificationUIManager()->CancelById(id, profile_id);
 }
 
 }  // namespace
 
 // static
 PlatformNotificationServiceImpl*
 PlatformNotificationServiceImpl::GetInstance() {
-  return Singleton<PlatformNotificationServiceImpl>::get();
+  return base::Singleton<PlatformNotificationServiceImpl>::get();
 }
 
 PlatformNotificationServiceImpl::PlatformNotificationServiceImpl()
     : notification_ui_manager_for_tests_(nullptr) {}
 
 PlatformNotificationServiceImpl::~PlatformNotificationServiceImpl() {}
 
 void PlatformNotificationServiceImpl::OnPersistentNotificationClick(
     BrowserContext* browser_context,
     int64_t persistent_notification_id,
@@ skipping 290 matching lines @@
         extensions::ExtensionRegistry::Get(profile)->GetExtensionById(
             origin.host(), extensions::ExtensionRegistry::EVERYTHING);
     DCHECK(extension);
 
     return base::UTF8ToUTF16(extension->name());
   }
 #endif
 
   return base::string16();
 }