Add an option in language settings for activating the IME menu.

chrome/browser/resources/options/language_options.css

 /* 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. */
 
 #languagePage .content-area {
   width: 660px;
 }
 
 .language-options {
   display: -webkit-box;
@@ skipping 73 matching lines @@
 }
 
 #language-options-input-method-list button {
   -webkit-margin-start: 20px;
   display: block;
   /* Same margin as .settings-row. */
   margin-bottom: 0.65em;
   margin-top: 0.65em;
 }
 
+.language-options-ime-menu-desc {
+  -webkit-margin-start: 18px;
+  font-size: 80%;
+  padding-bottom: 2px;
+}
+
 #language-options-list {
   -webkit-box-flex: 1;
   outline: none;
   padding: 0;
   width: 100%;
 }
 
 #language-options-list .language-name {
   -webkit-box-flex: 1;
   overflow: hidden;
@@ skipping 79 matching lines @@
 }
 
 #add-language-overlay-page .content-area {
   padding-bottom: 10px;
 }
 
 /* TODO(hshi): Remove this temporary hack once the bug is fixed in Chrome. */
 #add-language-overlay-language-list {
   width: -webkit-calc(100% - 4px);
 }