Make the user manager UI not permit guest mode when preferences dictate

chrome/browser/resources/user_manager/user_manager.js

Index: chrome/browser/resources/user_manager/user_manager.js
diff --git a/chrome/browser/resources/user_manager/user_manager.js b/chrome/browser/resources/user_manager/user_manager.js
index f6b8b593dcf3d22bdbae4b264242159c8c820d3c..84fab310838f06db9530d2f80d89a7b65d3e1eb0 100644
--- a/chrome/browser/resources/user_manager/user_manager.js
+++ b/chrome/browser/resources/user_manager/user_manager.js
@@ -34,13 +34,17 @@ cr.define('cr.ui', function() {
    * Shows the given screen.
    * @param {Object} screen Screen params dict, e.g. {id: screenId, data: data}
    */
-  Oobe.showUserManagerScreen = function() {
+  Oobe.showUserManagerScreen = function(showGuest) {
     Oobe.getInstance().showScreen({id: 'account-picker',
                                    data: {disableAddUser: false}});
     // The ChromeOS account-picker will hide the AddUser button if a user is
     // logged in and the screen is "locked", so we must re-enabled it
     $('add-user-header-bar-item').hidden = false;
 
+    // Hide the Guest Mode option if the user is not permitted to select it.
+    $('guest-user-button').hidden = !showGuest;
+    $('login-header-bar').hidden = false;
+
     // Disable the context menu, as the Print/Inspect element items don't
     // make sense when displayed as a widget.
     document.addEventListener('contextmenu', function(e) {e.preventDefault();});
@@ -130,6 +134,10 @@ cr.define('UserManager', function() {
     login.AccountPickerScreen.register();
     cr.ui.Bubble.decorate($('bubble'));
     login.HeaderBar.decorate($('login-header-bar'));
+
+    // Hide the header bar until the showUserManagerMethod can apply function
+    // parameters that affect widget visiblity.
+    $('login-header-bar').hidden = true;
     chrome.send('userManagerInitialize');
   }