MD History: Add routing for grouped history mode.

chrome/browser/resources/md_history/history_toolbar.js

 // 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.
 
 Polymer({
   is: 'history-toolbar',
   properties: {
     // Number of history items currently selected.
     // TODO(calamity): bind this to
     // listContainer.selectedItem.selectedPaths.length.
@@ skipping 125 matching lines @@
   },
 
   /** @private */
   numberOfItemsSelected_: function(count) {
     return count > 0 ? loadTimeData.getStringF('itemsSelected', count) : '';
   },
 
   /** @private */
   getHistoryInterval_: function() {
     var info = this.queryInfo;
+    if (!info)
+      return;

[calamity, 2017/01/27 03:47:34]

When can this happen?

[tsergeant, 2017/01/30 02:13:14]

It gets called when queryResult.info is set to null during initialization:
https://cs.chromium.org/chromium/src/chrome/browser/resources/md_history/app....

This already happens, but it just becomes a problem now because it's possible
for the `if` conditionals to be true.

+
     if (this.groupedRange == HistoryRange.WEEK)
       return info.queryInterval;
 
     if (this.groupedRange == HistoryRange.MONTH)
       return info.queryStartMonth;
   },
 
   /**
    * @param {Event} e
    * @private
@@ skipping 28 matching lines @@
   },
 
   /**
    * @private
    * @return {boolean}
    */
   isToday_: function() {
     return this.groupedOffset == 0;
   },
 });