Replace own callback handling with Promises.

ui/webui/resources/js/util.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.
 
 <include src="assert.js">
 
 /**
  * The global object.
  * @type {!Object}
  * @const
@@ skipping 383 matching lines @@
                  .replace(/"/g, '&quot;')
                  .replace(/'/g, '&#39;');
 }
 
 /**
  * Shortens the provided string (if necessary) to a string of length at most
  * |maxLength|.
  * @param {string} original The original string.
  * @param {number} maxLength The maximum length allowed for the string.
  * @return {string} The original string if its length does not exceed
- *     |maxLength|. Otherwise the first |maxLength| - 3 characters with '...'
+ *     |maxLength|. Otherwise the first |maxLength| - 1 characters with '...'
  *     appended.
  */
 function elide(original, maxLength) {
   if (original.length <= maxLength)
     return original;
-  return original.substring(0, maxLength - 3) + '...';
+  return original.substring(0, maxLength - 1) + '\u2026';
 }