The User Manager should be backed by a special profile, not the guest one.

chrome/browser/profiles/profile_window.h

 // Copyright 2013 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_PROFILES_PROFILE_WINDOW_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_WINDOW_H_
 
 #include "base/callback_forward.h"
 #include "chrome/browser/profiles/profile_metrics.h"
 #include "chrome/browser/ui/host_desktop.h"
@@ skipping 48 matching lines @@
 void CreateAndSwitchToNewProfile(chrome::HostDesktopType desktop_type,
                                  ProfileSwitchingDoneCallback callback,
                                  ProfileMetrics::ProfileAdd metric);
 
 // Closes all browser windows that belong to the guest profile.
 void CloseGuestProfileWindows();
 
 // Closes all the browser windows for |profile| and opens the user manager.
 void LockProfile(Profile* profile);
 
-// Creates or reuses the guest profile needed by the user manager. Based on
+// Creates or reuses the profile needed by the user manager. Based on
 // the value of |tutorial_mode|, the user manager can show a specific
 // tutorial, or no tutorial at all. If a tutorial is not shown, then
 // |profile_path_to_focus| could be used to specify which user should be
 // focused. |callback| is run with the custom url to be displayed, as well as
 // a pointer to the guest profile.
-void CreateGuestProfileForUserManager(
+void CreateUserManagerProfile(
     const base::FilePath& profile_path_to_focus,
     profiles::UserManagerTutorialMode tutorial_mode,
     const base::Callback<void(Profile*, const std::string&)>& callback);
 
 // Based on the |profile| preferences, determines whether a user manager
 // tutorial needs to be shown, and displays the user manager with or without
 // the tutorial.
 void ShowUserManagerMaybeWithTutorial(Profile* profile);
 
 }  // namespace profiles
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_WINDOW_H_