Move Singleton and related structs to namespace base

chrome/browser/media_galleries/media_file_system_registry.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/media_galleries/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 38 matching lines @@
 using storage_monitor::MediaStorageUtil;
 using storage_monitor::StorageInfo;
 using storage_monitor::StorageMonitor;
 
 namespace {
 
 class ShutdownNotifierFactory
     : public BrowserContextKeyedServiceShutdownNotifierFactory {
  public:
   static ShutdownNotifierFactory* GetInstance() {
-    return Singleton<ShutdownNotifierFactory>::get();
+    return base::Singleton<ShutdownNotifierFactory>::get();
   }
 
  private:
-  friend struct DefaultSingletonTraits<ShutdownNotifierFactory>;
+  friend struct base::DefaultSingletonTraits<ShutdownNotifierFactory>;
 
   ShutdownNotifierFactory()
       : BrowserContextKeyedServiceShutdownNotifierFactory(
             "MediaFileSystemRegistry") {
     DependsOn(MediaGalleriesPreferencesFactory::GetInstance());
   }
   ~ShutdownNotifierFactory() override {}
 
   DISALLOW_COPY_AND_ASSIGN(ShutdownNotifierFactory);
 };
@@ skipping 803 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   auto extension_hosts_it = extension_hosts_map_.find(profile);
   DCHECK(extension_hosts_it != extension_hosts_map_.end());
   extension_hosts_map_.erase(extension_hosts_it);
 
   auto profile_subscription_it = profile_subscription_map_.find(profile);
   DCHECK(profile_subscription_it != profile_subscription_map_.end());
   profile_subscription_map_.erase(profile_subscription_it);
 }