ntp4: fix app load/unload race condition

chrome/browser/resources/ntp4/tile_page.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.
 
 cr.define('ntp4', function() {
   'use strict';
 
   // We can't pass the currently dragging tile via dataTransfer because of
   // http://crbug.com/31037
   var currentlyDraggingTile = null;
@@ skipping 247 matching lines @@
           (e.propertyName == 'left' || e.propertyName == 'top' ||
            e.propertyName == '-webkit-transform')) {
         this.finalizeDrag_();
       }
     },
 
     /**
      * Called when an app is removed from Chrome. Animates its disappearance.
      */
     doRemove: function() {
-      var contents = this.firstChild;
       this.firstChild.classList.add('removing-tile-contents');
     },
 
     /**
      * Callback for the webkitAnimationEnd event on the tile's contents.
      * @param {Event} e The event object.
      */
     onContentsAnimationEnd_: function(e) {
       if (this.firstChild.classList.contains('new-tile-contents'))
         this.firstChild.classList.remove('new-tile-contents');
-      else if (this.firstChild.classList.contains('removing-tile-contents'))
+      if (this.firstChild.classList.contains('removing-tile-contents'))
         this.tilePage.removeTile(this);
     },
   };
 
   /**
    * Gives the proportion of the row width that is devoted to a single icon.
    * @param {number} rowTileCount The number of tiles in a row.
    * @return {number} The ratio between icon width and row width.
    */
   function tileWidthFraction(rowTileCount) {
@@ skipping 745 matching lines @@
     setDropEffect: function(dataTransfer) {
       assert(false);
     },
   };
 
   return {
     getCurrentlyDraggingTile: getCurrentlyDraggingTile,
     TilePage: TilePage,
   };
 });