Make table in chrome:site-engagement sortable.

chrome/browser/resources/engagement/engagement_table.css

 /* Copyright 2015 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. */
 
 table,
 table td,
 table th {
   border: 1px solid #777;
   border-collapse: collapse;
   padding-left: 4px;
   padding-right: 4px;
 }
 
 table th {
   background: rgb(224, 236, 255);
+  cursor: pointer;
+  padding-bottom: 4px;
+  padding-top: 4px;
+  white-space: nowrap;
 }
 
 .origin-cell {
   min-width: 500px;
 }
+
+table tr:hover {
+  background: rgb(255, 255, 187);
+}
+
+.sort-column::after {
+  content: '\25B2';
+}
+
+:host([sort-reverse_]) .sort-column::after {
+  content: '\25BC';
+}