[ChromeOS] Don't show empty account picker.

chrome/browser/resources/chromeos/login/oobe.js

 // 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.
 
 /**
  * @fileoverview Out of the box experience flow (OOBE).
  * This is the main code for the OOBE WebUI implementation.
  */
 
 var localStrings = new LocalStrings();
@@ skipping 138 matching lines @@
       $('oobe').className = nextStepId;
     },
 
     /**
      * Show screen of given screen id.
      * @param {Object} screen Screen params dict,
      *                        e.g. {id: screenId, data: data}
      */
     showScreen: function(screen) {
       var screenId = screen.id;
+
+      // Show sign-in screen instead of account picker if pod row is empty.
+      if (screenId == SCREEN_ACCOUNT_PICKER && $('pod-row').pods.length == 0) {
+        Oobe.showSigninUI();
+        return;
+      }
+
       var data = screen.data;
       var index = this.getScreenIndex_(screenId);
       if (index >= 0)
         this.toggleStep_(index, data);
       $('offline-message').update();
     },
 
     /**
      * Gets index of given screen id in screens_.
      * @param {string} screenId Id of the screen to look up.
@@ skipping 272 matching lines @@
     return !document.body.classList.contains('login-display');
   };
 
   /**
    * Shows signin UI.
    * @param {string} opt_email An optional email for signin UI.
    */
   Oobe.showSigninUI = function(opt_email) {
     $('add-user-button').hidden = true;
     $('cancel-add-user-button').hidden = false;
+    $('add-user-header-bar-item').hidden = $('pod-row').pods.length == 0;
     chrome.send('showAddUser', [opt_email]);
   };
 
   /**
    * Resets sign-in input fields.
    */
   Oobe.resetSigninUI = function() {
     var currentScreenId = Oobe.getInstance().currentScreen.id;
 
     if (localStrings.getString('authType') == 'webui')
@@ skipping 105 matching lines @@
 document.onselectstart = function(e) {
   e.preventDefault();
 }
 
 // Disable dragging.
 document.ondragstart = function(e) {
   e.preventDefault();
 }
 
 document.addEventListener('DOMContentLoaded', cr.ui.Oobe.initialize);