Add histgrams to Folder shortcut feature in Files.app.

chrome/browser/resources/file_manager/js/navigation_list.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.
 
 'use strict';
 
 /**
  * A navigation list model. This model combines the 2 lists.
  * @param {cr.ui.ArrayDataModel} volumesList The first list of the model.
  * @param {cr.ui.ArrayDataModel} pinnedList The second list of the model.
@@ skipping 295 matching lines @@
  * @param {string} path Path of the directory to be rendered.
  * @return {NavigationListItem} Rendered element.
  * @private
  */
 NavigationList.prototype.renderRoot_ = function(path) {
   var item = new NavigationListItem();
   item.setPath(path);
 
   var handleClick = function() {
     if (item.selected && path !== this.directoryModel_.getCurrentDirPath()) {
+      metrics.recordUserAction('FolderShortcut.Navigate');
       this.directoryModel_.changeDirectory(path);
     }
   }.bind(this);
   item.addEventListener('click', handleClick);
 
   var handleEject = function() {
     var unmountCommand = cr.doc.querySelector('command#unmount');
     // Let's make sure 'canExecute' state of the command is properly set for
     // the root before executing it.
     unmountCommand.canExecuteChange(item);
@@ skipping 16 matching lines @@
 NavigationList.prototype.setContextMenu = function(menu) {
   this.contextMenu_ = menu;
 
   for (var i = 0; i < this.dataModel.length; i++) {
     this.getListItemByIndex(i).maybeSetContextMenu(this.contextMenu_);
   }
 };
 
 /**
  * Selects the n-th item from the list.
+ *
  * @param {number} index Item index.
  * @return {boolean} True for success, otherwise false.
  */
 NavigationList.prototype.selectByIndex = function(index) {
   if (index < 0 || index > this.dataModel.length - 1)
     return false;
 
   var newPath = this.dataModel.item(index);
   if (!newPath)
     return false;
 
   // Prevents double-moving to the current directory.
+  // eg. When user clicks the item, changing directory has already been done in
+  //     click handler.
   if (this.directoryModel_.getCurrentDirEntry().fullPath == newPath)
     return false;
 
+  metrics.recordUserAction('FolderShortcut.Navigate');
   this.directoryModel_.changeDirectory(newPath);
   return true;
 };
 
 /**
  * Handler before root item change.
  * @param {Event} event The event.
  * @private
  */
 NavigationList.prototype.onBeforeSelectionChange_ = function(event) {
@@ skipping 70 matching lines @@
     var itemPath = this.dataModel.item(i);
     if (PathUtil.getRootPath(itemPath) == newRootPath) {
       // Not to invoke the handler of this instance, sets the guard.
       this.dontHandleSelectionEvent_ = true;
       this.selectionModel.selectedIndex = i;
       this.dontHandleSelectionEvent_ = false;
       return;
     }
   }
 };