MD History/Downloads: convert .bind(this) and function property values to use =>

chrome/browser/resources/md_downloads/manager.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.
 
 cr.define('downloads', function() {
   var Manager = Polymer({
     is: 'downloads-manager',
 
     properties: {
       /** @private */
@@ skipping 11 matching lines @@
 
       /** @private */
       inSearchMode_: {
         type: Boolean,
         value: false,
       },
 
       /** @private {!Array<!downloads.Data>} */
       items_: {
         type: Array,
-        value: function() { return []; },
+        value: () => [],
       },
 
       /** @private */
       spinnerActive_: {
         type: Boolean,
         notify: true,
       },
     },
 
     hostAttributes: {
@@ skipping 165 matching lines @@
   Manager.removeItem = function(index) {
     Manager.get().removeItem_(index);
   };
 
   Manager.updateItem = function(index, data) {
     Manager.get().updateItem_(index, data);
   };
 
   return {Manager: Manager};
 });