Settings page sliding transition

chrome/browser/resources/options/browser_options.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 Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
   var ArrayDataModel = cr.ui.ArrayDataModel;
   var RepeatingButton = cr.ui.RepeatingButton;
@@ skipping 727 matching lines @@
       // end event as the upcoming code will cancel the current one.
       if (section.classList.contains('sliding'))
         cr.dispatchSimpleEvent(section, 'webkitTransitionEnd');
 
       this.addTransitionEndListener_(section);
 
       section.hidden = false;
       section.style.height = (showing ? 0 : container.offsetHeight) + 'px';
       section.classList.add('sliding');
 
+      // Force a style recalc before starting the animation.

[Dan Beam, 2014/09/10 22:56:34]

can you please add a 

  /** @suppress {uselessCode} */
  section.offsetHeight;

to make the closure compiler happy?

[michaelpg, 2014/09/10 23:19:52]

Done.

+      section.offsetHeight;
+
       if (this.sectionHeightChangeTimeout_ !== null)
         clearTimeout(this.sectionHeightChangeTimeout_);
 
       this.sectionHeightChangeTimeout_ = setTimeout(function() {
         section.style.height = (showing ? container.offsetHeight : 0) + 'px';
         this.sectionHeightChangeTimeout_ = null;
       });

[Dan Beam, 2014/09/10 22:56:34]

i don't think you need anything involving setTimeout() if you're flushing styles
with .offsetHeight.  you can probably remove anything to do with
|this.sectionHeightChangeTimeout_|.

[michaelpg, 2014/09/10 23:19:52]

Done.

     },
 
     /**
      * Shows the given section.
      * @param {HTMLElement} section The section to be shown.
      * @param {HTMLElement} container The container for the section. Must be
      *     inside of |section|.
      * @param {boolean} animate Indicate if the expansion should be animated.
      * @private
      */
@@ skipping 1209 matching lines @@
     BrowserOptions.getLoggedInUsername = function() {
       return BrowserOptions.getInstance().username_;
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });