Move Singleton and related structs to namespace base

chrome/browser/extensions/extension_assets_manager.cc

 // Copyright (c) 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/extensions/extension_assets_manager.h"
 
 #include "base/memory/singleton.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/file_util.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/extensions/extension_assets_manager_chromeos.h"
 #endif
 
 namespace extensions {
 namespace {
 
 class ExtensionAssetsManagerImpl :  public ExtensionAssetsManager {
  public:
   static ExtensionAssetsManagerImpl* GetInstance() {
-    return Singleton<ExtensionAssetsManagerImpl>::get();
+    return base::Singleton<ExtensionAssetsManagerImpl>::get();
   }
 
   // Override from ExtensionAssetsManager.
   void InstallExtension(const Extension* extension,
                         const base::FilePath& unpacked_extension_root,
                         const base::FilePath& local_install_dir,
                         Profile* profile,
                         InstallExtensionCallback callback) override {
     callback.Run(file_util::InstallExtension(
         unpacked_extension_root,
         extension->id(),
         extension->VersionString(),
         local_install_dir));
   }
 
   void UninstallExtension(const std::string& id,
                           Profile* profile,
                           const base::FilePath& local_install_dir,
                           const base::FilePath& extension_root) override {
     file_util::UninstallExtension(local_install_dir, id);
   }
 
  private:
-  friend struct DefaultSingletonTraits<ExtensionAssetsManagerImpl>;
+  friend struct base::DefaultSingletonTraits<ExtensionAssetsManagerImpl>;
 
   ExtensionAssetsManagerImpl() {}
   ~ExtensionAssetsManagerImpl() override {}
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAssetsManagerImpl);
 };
 
 }  // namespace
 
 // static
 ExtensionAssetsManager* ExtensionAssetsManager::GetInstance() {
 #if defined(OS_CHROMEOS)
   return ExtensionAssetsManagerChromeOS::GetInstance();
 #else
   // If not Chrome OS, use trivial implementation that doesn't share anything.
   return ExtensionAssetsManagerImpl::GetInstance();
 #endif  // OS_CHROMEOS
 }
 
 }  // namespace extensions