Move Singleton and related structs to namespace base

chrome/browser/extensions/extension_assets_manager_chromeos.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_ASSETS_MANAGER_CHROMEOS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_ASSETS_MANAGER_CHROMEOS_H_
 
 #include <map>
 
 #include "chrome/browser/extensions/extension_assets_manager.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
+
 class PrefRegistrySimple;
 
 namespace base {
 class DictionaryValue;
 class SequencedTaskRunner;
 }
 
 namespace extensions {
 
 // Chrome OS specific implementation of assets manager that shares default apps
@@ skipping 34 matching lines @@
   // Cleans up shared extensions list in preferences and returns list of
   // extension IDs and version paths that are in use in |live_extension_paths|.
   // Files on disk are not removed. Must be called on UI thread.
   // Returns |false| in case of errors.
   static bool CleanUpSharedExtensions(
       std::multimap<std::string, base::FilePath>* live_extension_paths);
 
   static void SetSharedInstallDirForTesting(const base::FilePath& install_dir);
 
  private:
-  friend struct DefaultSingletonTraits<ExtensionAssetsManagerChromeOS>;
+  friend struct base::DefaultSingletonTraits<ExtensionAssetsManagerChromeOS>;
 
   ExtensionAssetsManagerChromeOS();
   ~ExtensionAssetsManagerChromeOS() override;
 
   // Should be called on UI thread to get associated file task runner for
   // the profile.
   static base::SequencedTaskRunner* GetFileTaskRunner(Profile* profile);
 
   // Return |true| if |extension| can be installed in a shared place for all
   // users on the device.
@@ skipping 43 matching lines @@
       const std::string& id,
       base::DictionaryValue* extension_info,
       std::multimap<std::string, base::FilePath>* live_extension_paths);
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAssetsManagerChromeOS);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ASSETS_MANAGER_CHROMEOS_H_