History: Add load-time metric for non-MD and MD History WebUI

chrome/browser/resources/history/history.js

 // Copyright (c) 2012 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.
 
 <include src="../uber/uber_utils.js">
 <include src="history_focus_manager.js">
 
 ///////////////////////////////////////////////////////////////////////////////
 // Globals:
 /** @const */ var RESULTS_PER_PAGE = 150;
@@ skipping 921 matching lines @@
  */
 function HistoryView(model) {
   this.editButtonTd_ = $('edit-button');
   this.editingControlsDiv_ = $('editing-controls');
   this.resultDiv_ = $('results-display');
   this.focusGrid_ = new cr.ui.FocusGrid();
   this.pageDiv_ = $('results-pagination');
   this.model_ = model;
   this.pageIndex_ = 0;
   this.lastDisplayed_ = [];
+  this.hasRenderedResults_ = false;
 
   this.model_.setView(this);
 
   this.currentVisits_ = [];
 
   // If there is no search button, use the search button label as placeholder
   // text in the search field.
   if ($('search-button').offsetWidth == 0)
     $('search-field').placeholder = $('search-button').value;
 
@@ skipping 163 matching lines @@
   document.body.classList.toggle('has-results', hasResults);
 
   this.updateFocusGrid_();
   this.updateNavBar_();
 
   if (isMobileVersion()) {
     // Hide the search field if it is empty and there are no results.
     var isSearch = this.model_.getSearchText().length > 0;
     $('search-field').hidden = !(hasResults || isSearch);
   }
+
+  if (!this.hasRenderedResults_) {
+    this.hasRenderedResults_ = true;
+    requestAnimationFrame(function() {
+      chrome.send(
+          'metricsHandler:recordTime',
+          ['History.ResultsRenderedTime', window.performance.now()]);
+    });
+  }
 };
 
 /**
  * Enables or disables the buttons that control editing entries depending on
  * whether there are any checked boxes.
  */
 HistoryView.prototype.updateSelectionEditButtons = function() {
   if (loadTimeData.getBoolean('allowDeletingHistory')) {
     var anyChecked = document.querySelector('.entry input:checked') != null;
     $('remove-selected').disabled = !anyChecked;
@@ skipping 1268 matching lines @@
     historyView.reload();
 }
 
 // Add handlers to HTML elements.
 document.addEventListener('DOMContentLoaded', load);
 
 // This event lets us enable and disable menu items before the menu is shown.
 document.addEventListener('canExecute', function(e) {
   e.canExecute = true;
 });