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

chrome/browser/resources/options/managed_user_settings.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.
 
 if (loadTimeData.getBoolean('managedUsersEnabled')) {
 
 cr.define('options', function() {
   /** @const */ var OptionsPage = options.OptionsPage;
 
   //////////////////////////////////////////////////////////////////////////////
@@ skipping 10 matching lines @@
         'manageduser',
         loadTimeData.getString('managedUserSettingsPageTabTitle'),
         'managed-user-settings-page');
   }
 
   cr.addSingletonGetter(ManagedUserSettings);
 
   ManagedUserSettings.prototype = {
     // Inherit from OptionsPage.
     __proto__: OptionsPage.prototype,
+    authenticationChecked: false,
+    authenticationChecking: false,
 
     /**
      * Initialize the page.
      * @override
      */
     initializePage: function() {
+      var self = this;
       // Call base class implementation to start preference initialization.
       OptionsPage.prototype.initializePage.call(this);
 
       $('get-content-packs-button').onclick = function(event) {
         window.open(loadTimeData.getString('getContentPacksURL'));
       };
 
       $('managed-user-settings-confirm').onclick = function() {
-        OptionsPage.closeOverlay();
+        if ($('use-passphrase-checkbox').checked) {
+          chrome.send('isPassphraseSet');
+        } else {
+          OptionsPage.closeOverlay();
+        }
       };
 
       $('set-passphrase').onclick = function() {
-        // TODO(bauerb): Set passphrase
+        OptionsPage.navigateToPage('setPassphrase');
       };
     },
+    /** @override */
+    canShowPage: function() {
+      if (this.authenticationChecked)
+        return true;
+      if (!this.authenticationChecking) {
+        chrome.send('displayPassphraseDialog',
+            ['ManagedUserSettings.isAuthenticated']);
+        this.authenticationChecking = true;
+      }
+      return false;
+    },
+    didClosePage: function() {
+      // Reset the authentication of the custodian.
+      this.authenticationChecked = false;
+      chrome.send('endAuthentication');
+    },
   };
 
+  ManagedUserSettings.isAuthenticated = function(success) {
+    var instance = ManagedUserSettings.getInstance();
+    if (success) {
+      instance.authenticationChecked = true;
+      OptionsPage.navigateToPage('managedUser');
+    } else {
+      OptionsPage.closeOverlay();
+    }
+    instance.authenticationChecking = false;
+  };
+
+  ManagedUserSettings.isPassphraseSet = function(success) {
+    if (success) {
+      OptionsPage.closeOverlay();
+    } else {
+      OptionsPage.navigateToPage('setPassphrase');
+    }
+  };
+
    // Export
   return {
     ManagedUserSettings: ManagedUserSettings
   };
 });
 
 }