Move Singleton and related structs to namespace base

chrome/browser/chromeos/upgrade_detector_chromeos.cc

 // Copyright (c) 2012 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/chromeos/upgrade_detector_chromeos.h"
 
 #include "base/memory/singleton.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/update_engine_client.h"
 
@@ skipping 132 matching lines @@
   // Setup timer to to move along the upgrade advisory system.
   upgrade_notification_timer_.Start(
       FROM_HERE,
       base::TimeDelta::FromMilliseconds(kNotifyCycleTimeMs),
       this,
       &UpgradeDetectorChromeos::NotifyOnUpgrade);
 }
 
 // static
 UpgradeDetectorChromeos* UpgradeDetectorChromeos::GetInstance() {
-  return Singleton<UpgradeDetectorChromeos>::get();
+  return base::Singleton<UpgradeDetectorChromeos>::get();
 }
 
 // static
 UpgradeDetector* UpgradeDetector::GetInstance() {
   return UpgradeDetectorChromeos::GetInstance();
 }