Remove ibus-hangul support.

chrome/browser/resources/options/language_options.js

 // Copyright (c) 2011 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.
 
 // TODO(kochi): Generalize the notification as a component and put it
 // in js/cr/ui/notification.js .
 
 cr.define('options', function() {
   const OptionsPage = options.OptionsPage;
   const LanguageList = options.LanguageList;
 
   // Some input methods like Chinese Pinyin have config pages.
   // This is the map of the input method names to their config page names.
   const INPUT_METHOD_ID_TO_CONFIG_PAGE_NAME = {
-    // TODO(nona): Remove ibus-hangul support.
-    'hangul': 'languageHangul',
     'mozc': 'languageMozc',
     'mozc-chewing': 'languageChewing',
     'mozc-dv': 'languageMozc',
     'mozc-hangul': 'languageHangul',
     'mozc-jp': 'languageMozc',
     'pinyin': 'languagePinyin',
     'pinyin-dv': 'languagePinyin',
   };
 
   /////////////////////////////////////////////////////////////////////////////
@@ skipping 770 matching lines @@
   LanguageOptions.uiLanguageSaved = function() {
     $('language-options-ui-language-button').style.display = 'none';
     $('language-options-ui-notification-bar').style.display = 'block';
   };
 
   // Export
   return {
     LanguageOptions: LanguageOptions
   };
 });