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

chrome/browser/resources/settings/languages_page/edit_dictionary_page.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.
 
 /**
  * @fileoverview 'settings-edit-dictionary-page' is a sub-page for editing
  * the "dictionary" of custom words used for spell check.
  */
 Polymer({
   is: 'settings-edit-dictionary-page',
@@ skipping 24 matching lines @@
 
   /** @type {LanguageSettingsPrivate} */
   languageSettingsPrivate: null,
 
   /** @override */
   ready: function() {
     this.languageSettingsPrivate = settings.languageSettingsPrivateApiForTest ||
         /** @type {!LanguageSettingsPrivate} */
         (chrome.languageSettingsPrivate);
 
-    this.languageSettingsPrivate.getSpellcheckWords(function(words) {
+    this.languageSettingsPrivate.getSpellcheckWords(words => {
       this.words_ = words;
-    }.bind(this));
+    });
 
     this.languageSettingsPrivate.onCustomDictionaryChanged.addListener(
         this.onCustomDictionaryChanged_.bind(this));
 
     // Add a key handler for the paper-input.
     this.$.keys.target = this.$.newWord;
   },
 
   /**
    * Check if the new word text-field is empty.
@@ skipping 78 matching lines @@
 
   /**
    * Checks if any words exists in the dictionary.
    * @private
    * @return {boolean}
    */
   hasWords_: function() {
     return this.words_.length > 0;
   }
 });