Comb up ownership things.

chrome/browser/chromeos/login/user_manager.h

 // Copyright (c) 2011 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_CHROMEOS_LOGIN_USER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USER_MANAGER_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "base/ref_counted.h"
+#include "base/synchronization/lock.h"
 #include "chrome/browser/chromeos/login/user_image_loader.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 class FilePath;
 class PrefService;
 
+namespace base {
+template<typename> struct DefaultLazyInstanceTraits;
+}
+
 namespace chromeos {
 class RemoveUserDelegate;
 
 // This class provides a mechanism for discovering users who have logged
 // into this chromium os device before and updating that list.
 class UserManager : public UserImageLoader::Delegate,
                     public NotificationObserver {
  public:
   // A class representing information about a previously logged in user.
   class User {
@@ skipping 109 matching lines @@
   scoped_refptr<UserImageLoader> image_loader_;
 
   // Cache for user images. Stores image for each username.
   typedef base::hash_map<std::string, SkBitmap> UserImages;
   mutable UserImages user_images_;
 
   // The logged-in user.
   User logged_in_user_;
 
   // Cached flag of whether currently logged-in user is owner or not.
+  // May be accessed on different threads, requires locking.
   bool current_user_is_owner_;
+  mutable base::Lock current_user_is_owner_lock_;
 
   // Cached flag of whether the currently logged-in user existed before this
   // login.
   bool current_user_is_new_;
 
   // Cached flag of whether any user is logged in at the moment.
   bool user_is_logged_in_;
 
   NotificationRegistrar registrar_;
 
+  friend struct base::DefaultLazyInstanceTraits<UserManager>;
+
   DISALLOW_COPY_AND_ASSIGN(UserManager);
 };
 
 typedef std::vector<UserManager::User> UserVector;
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USER_MANAGER_H_