Add a lock to the managed user settings page and require authentication for unlocking.

chrome/browser/resources/options/manage_profile_overlay.js

 // 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.
 
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var ArrayDataModel = cr.ui.ArrayDataModel;
 
   /**
    * ManageProfileOverlay class
@@ skipping 34 matching lines @@
       options.ProfilesIconGrid.decorate($('create-profile-icon-grid'));
       self.registerCommonEventHandlers_('create',
                                         self.submitCreateProfile_.bind(self));
       self.registerCommonEventHandlers_('manage',
                                         self.submitManageChanges_.bind(self));
 
       if (loadTimeData.getBoolean('managedUsersEnabled')) {
         $('create-profile-managed-container').hidden = false;
         $('managed-user-settings-button').onclick = function(event) {
           OptionsPage.navigateToPage('managedUser');
-          chrome.send('coreOptionsUserMetricsAction',
-                      ['Options_ManagedUserPassphraseOverlay']);
         };
       }
       $('manage-profile-cancel').onclick =
           $('delete-profile-cancel').onclick =
               $('create-profile-cancel').onclick = function(event) {
         OptionsPage.closeOverlay();
       };
       $('delete-profile-ok').onclick = function(event) {
         OptionsPage.closeOverlay();
         chrome.send('deleteProfile', [self.profileInfo_.filePath]);
@@ skipping 354 matching lines @@
       $('create-profile-ok').disabled = true;
     },
   };
 
   // Export
   return {
     ManageProfileOverlay: ManageProfileOverlay,
     CreateProfileOverlay: CreateProfileOverlay,
   };
 });