[MD History] Add UMA stats for switching views and the CBD button.

chrome/browser/resources/md_history/list_container.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.
 
 Polymer({
   is: 'history-list-container',
 
   properties: {
     // The path of the currently selected page.
     selectedPage_: String,
 
     // Whether domain-grouped history is enabled.
     grouped: Boolean,
 
+    /** @type {HistoryRange} */
+    groupedRange: {type: Number, observer: 'groupedRangeChanged_'},
+
     /** @type {!QueryState} */
     queryState: Object,
 
     /** @type {!QueryResult} */
     queryResult: Object,
   },
 
-  observers: [
-    'groupedRangeChanged_(queryState.range)',
-  ],
-
   listeners: {
     'history-list-scrolled': 'closeMenu_',
     'load-more-history': 'loadMoreHistory_',
     'toggle-menu': 'toggleMenu_',
   },
 
   /**
    * @param {HistoryQuery} info An object containing information about the
    *    query.
    * @param {!Array<HistoryEntry>} results A list of results.
@@ skipping 36 matching lines @@
     this.set('queryState.querying', true);
     this.set('queryState.incremental', incremental);
 
     var lastVisitTime = 0;
     if (incremental) {
       var lastVisit = this.queryResult.results.slice(-1)[0];
       lastVisitTime = lastVisit ? lastVisit.time : 0;
     }
 
     var maxResults =
-      queryState.range == HistoryRange.ALL_TIME ? RESULTS_PER_PAGE : 0;
+      this.groupedRange == HistoryRange.ALL_TIME ? RESULTS_PER_PAGE : 0;
     chrome.send('queryHistory', [
       queryState.searchTerm, queryState.groupedOffset, queryState.range,
       lastVisitTime, maxResults
     ]);
   },
 
   unselectAllItems: function(count) {
     this.getSelectedList_().unselectAllItems(count);
   },
 
   /**
    * Delete all the currently selected history items. Will prompt the user with
    * a dialog to confirm that the deletion should be performed.
    */
   deleteSelectedWithPrompt: function() {
     if (!loadTimeData.getBoolean('allowDeletingHistory'))
       return;
 
     this.$.dialog.showModal();
   },
 
   /**
    * @param {HistoryRange} range
    * @private
    */
-  groupedRangeChanged_: function(range) {
-    this.selectedPage_ = this.queryState.range == HistoryRange.ALL_TIME ?
+  groupedRangeChanged_: function(range, oldRange) {
+    this.selectedPage_ = range == HistoryRange.ALL_TIME ?
       'infinite-list' : 'grouped-list';
 
+    if (oldRange == undefined)
+      return;
+
     this.queryHistory(false);
+    this.fire('history-view-changed');
   },
 
   /** @private */
   loadMoreHistory_: function() { this.queryHistory(true); },
 
   /**
    * @param {HistoryQuery} info
    * @param {!Array<HistoryEntry>} results
    * @private
    */
@@ skipping 69 matching lines @@
   },
 
   /**
    * @return {HTMLElement}
    * @private
    */
   getSelectedList_: function() {
     return this.$.content.selectedItem;
   },
 });