MD Settings: Convert all usages of .bind(this) to use ES6 arrow function.

chrome/browser/resources/settings/languages_page/add_languages_dialog.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.
 
 /**
  * @fileoverview 'settings-add-languages-dialog' is a dialog for enabling
  * languages.
  */
 Polymer({
   is: 'settings-add-languages-dialog',
@@ skipping 47 matching lines @@
   },
 
   /**
    * @return {!Array<!chrome.languageSettingsPrivate.Language>} A list of
    *     languages to be displayed.
    * @private
    */
   getLanguages_: function() {
     var filterValue =
         this.filterValue_ ? this.filterValue_.toLowerCase() : null;
-    return this.languages.supported.filter(function(language) {
+    return this.languages.supported.filter(language => {
       var isAvailableLanguage =
           !this.languageHelper.isLanguageEnabled(language.code);
 
       if (!isAvailableLanguage)
         return false;
 
       if (filterValue === null)
         return true;
 
       return language.displayName.toLowerCase().includes(filterValue) ||
           language.nativeDisplayName.toLowerCase().includes(filterValue);
-    }.bind(this));
+    });
   },
 
   /**
    * @param {!chrome.languageSettingsPrivate.Language} language
    * @return {string} The text to be displayed.
    * @private
    */
   getDisplayText_: function(language) {
     var displayText = language.displayName;
     // If the native name is different, add it.
@@ skipping 36 matching lines @@
   onCancelButtonTap_: function() {
     this.$.dialog.close();
   },
 
   /**
    * Enables the checked languages.
    * @private
    */
   onActionButtonTap_: function() {
     this.$.dialog.close();
-    this.languagesToAdd_.forEach(function(languageCode) {
+    this.languagesToAdd_.forEach(languageCode => {
       this.languageHelper.enableLanguage(languageCode);
-    }.bind(this));
+    });
   },
 });