Polished update screen.

chrome/browser/resources/chromeos/login/oobe_screen_update.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.
 
 /**
  * @fileoverview Oobe update screen implementation.
  */
 
 cr.define('oobe', function() {
   /**
    * Creates a new oobe screen div.
    * @constructor
    * @extends {HTMLDivElement}
    */
   var UpdateScreen = cr.ui.define('div');
 
-  /** @const */ var ELLIPSIS = ['', '.', '..', '...'];
-  /** @const */ var ELLIPSIS_ANIMATION_TIMEOUT_MS = 1000;
-
   /**
    * Registers with Oobe.
    */
   UpdateScreen.register = function() {
     var screen = $('update');
     UpdateScreen.decorate(screen);
     Oobe.getInstance().registerScreen(screen);
   };
 
   UpdateScreen.prototype = {
     __proto__: HTMLDivElement.prototype,
 
     /** @override */
     decorate: function() {
     },
 
-    onBeforeShow: function(data) {
-      UpdateScreen.startEllipsisAnimation();

[Nikita (slow), 2013/04/10 04:52:05]

I think you should specifically add rule like "display: none"  when screen is
hidden and remove that when screen is shown to prevent animation happening when
visibility is hidden.

[Nikita (slow), 2013/04/12 12:54:39]

What about this comment?

-    },
-
-    onBeforeHide: function() {
-      UpdateScreen.stopEllipsisAnimation();
-    },
-
     /**
      * Header text of the screen.
      * @type {string}
      */
     get header() {
       return loadTimeData.getString('updateScreenTitle');
     },
 
     /**
-     * Buttons in oobe wizard's button strip.
-     * @type {array} Array of Buttons.
-     */
-    get buttons() {
-      return null;
-    },
-
-    /**
      * Cancels the screen.
      */
     cancel: function() {
       // It's safe to act on the accelerator even if it's disabled on official
       // builds, since Chrome will just ignore the message in that case.
       var updateCancelHint = $('update-cancel-hint').firstElementChild;
       updateCancelHint.textContent =
           loadTimeData.getString('cancelledUpdateMessage');
       chrome.send('cancelUpdate');
     },
   };
 
-  var ellipsisAnimationActive = false;
-
-  /**
-   * Updates number of dots in the ellipsis.
-   *
-   * @private
-   * @param {number} count Number of dots that should be shown.
-   */
-  function updateEllipsisAnimation_(count) {
-    $('update-checking-ellipsis').textContent = ELLIPSIS[count];
-    if (ellipsisAnimationActive) {
-      window.setTimeout(function() {
-          updateEllipsisAnimation_((count + 1) % ELLIPSIS.length);
-        }, ELLIPSIS_ANIMATION_TIMEOUT_MS);
-    }
-  };
-
   /**
    * Makes 'press Escape to cancel update' hint visible.
    */
   UpdateScreen.enableUpdateCancel = function() {
     $('update-cancel-hint').hidden = false;
   };
 
-  /**
-   * Starts animation for tail ellipses in "Checking for update..." label.
-   */
-  UpdateScreen.startEllipsisAnimation = function() {
-    ellipsisAnimationActive = true;
-    updateEllipsisAnimation_(0);
-  };
-
-  /**
-   * Stops animation for tail ellipses in "Checking for update..." label.
-   */
-  UpdateScreen.stopEllipsisAnimation = function() {
-    ellipsisAnimationActive = false;
-  };
-
   return {
     UpdateScreen: UpdateScreen
   };
 });