Use drop-down UI for "add language".

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. */
 
 .language-options {
   display: -webkit-box;
   margin: 10px 0;
 }
 
 .language-options-lower-left button,
@@ skipping 109 matching lines @@
   border-top-color: transparent;
   box-sizing: border-box;
   display: none;
   height: 8px;
   overflow: hidden;
   pointer-events: none;
   position: fixed;
   z-index: 10;
 }
 
-/* In ChromeOS we present the language choices as a big page of links. */
-<if expr="pp_ifdef('chromeos')">
-#add-language-overlay-language-list {
-  -webkit-column-count: 2;
-  -webkit-column-gap: 20px;
-}
-
-#add-language-overlay-language-list > li > button.link-button {
-  padding-bottom: 8px;
-  padding-top: 8px;
-}
-
-#add-language-overlay-page {
-  width: 800px;
-}
-
-#add-language-overlay-page button.link-button {
-  padding-left: 0;
-  padding-right: 0;
-  text-align: left;
-}
-
-#add-language-overlay-page ul {
-  margin: 0;
-  padding: 0;
-}
-</if>
-
 /* TODO(kochi): This is temporary copy from new_tab.css */
 /* Notification */
 
 #notification {
   -webkit-transition: opacity 150ms;
   background-color: hsl(52, 100%, 80%);
   border: 1px solid rgb(211, 211, 211);
   border-radius: 6px;
   color: black;
   display: table;
@@ skipping 42 matching lines @@
   width: 100px;
 }
 
 #add-language-overlay-page .content-area {
   padding-bottom: 10px;
 }
 
 .standalone-link-button {
   padding: 0;
 }