[MD History] Copy stats from the old history page.

chrome/browser/resources/md_history/grouped_list.js

 // Copyright 2016 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.
 
 /**
  * @typedef {{domain: string,
  *            visits: !Array<HistoryEntry>,
  *            rendered: boolean,
  *            expanded: boolean}}
  */
@@ skipping 108 matching lines @@
       pushCurrentDay();
 
       this.groupedHistoryData_ = days;
     } else if (this.range == HistoryRange.MONTH) {
       // Group each all visits into a single list.
       this.groupedHistoryData_ = [{
         title: this.queryStartTime + ' – ' + this.queryEndTime,
         domains: this.createHistoryDomains_(this.historyData)
       }];
     }
+
+    this.addItemIndexes();
+  },
+
+  addItemIndexes: function() {
+    var index = 0;
+    this.groupedHistoryData_.forEach(function(group) {
+      group.domains.forEach(function(domain) {
+        domain.visits.forEach(function(visit) {
+          visit.index = index++;
+        });
+      });
+    });
   },
 
   /**
    * @param {{model:Object, currentTarget:IronCollapseElement}} e
    */
   toggleDomainExpanded_: function(e) {
     var collapse = e.currentTarget.parentNode.querySelector('iron-collapse');
     e.model.set('domain.rendered', true);
 
     // Give the history-items time to render.
@@ skipping 43 matching lines @@
 
   /**
    * @param {boolean} expanded
    * @return {string}
    * @private
    */
   getDropdownIcon_: function(expanded) {
     return expanded ? 'cr:expand-less' : 'cr:expand-more';
   },
 });