[MD History] Fix toolbar dates in grouped mode.

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 17 matching lines @@
     },
 
     /**
      * @type {Array<HistoryGroup>}
      */
     groupedHistoryData_: Array,
 
     // An array of history entries in reverse chronological order.
     historyData: Array,
 
-    queryStartTime: String,
-
-    queryEndTime: String,
+    queryInterval: String,
 
     range: Number,
   },
 
   observers: ['updateGroupedHistoryData_(range, historyData)'],
 
   /**
    * @param {!Array<!HistoryEntry>} results
    * @param {boolean} incremental
    * @param {boolean} finished
@@ skipping 67 matching lines @@
           currentDayVisits = [];
         }
         currentDayVisits.push(visit);
       }
       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,
+        title: this.queryInterval,
         domains: this.createHistoryDomains_(this.historyData)
       }];
     }
   },
 
   /**
    * @param {{model:Object, currentTarget:IronCollapseElement}} e
    */
   toggleDomainExpanded_: function(e) {
     var collapse = e.currentTarget.parentNode.querySelector('iron-collapse');
@@ skipping 47 matching lines @@
 
   /**
    * @param {boolean} expanded
    * @return {string}
    * @private
    */
   getDropdownIcon_: function(expanded) {
     return expanded ? 'cr:expand-less' : 'cr:expand-more';
   },
 });