Fixed Android NTP bookmark directory line RTL UI.

chrome/browser/resources/ntp_android/bookmarks.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. */
 
 /* Begin top bar */
 
 #bookmarks_title_wrapper {
   border-bottom: 1px solid #d0d0d0;
   display: -webkit-box;
   font-size: 17px;
@@ skipping 49 matching lines @@
 
 .bookmark-separator {
   background-image: url(images/breadcrumb_mdpi.png);
   background-position: center;
   background-repeat: no-repeat;
   background-size: 8px 20px; /* this matches the background image size */
   height: 44px;
   width: 10px;
 }
 
+html[dir='rtl'] .bookmark-separator {
+  -webkit-transform: scaleX(-1);
+}
+
 #bookmarks_title_wrapper .title-crumb {
   color: #555;
   margin: 0 10px;
 }
 
 #bookmarks_title_wrapper .title-crumb-active {
   font-weight: bold;
   margin-right: 0;
   padding-right: 10px;
 }
@@ skipping 179 matching lines @@
   .bookmark-border {
     background-image: url(images/bookmark_border_xhdpi.png);
   }
   .favicon-box.folder {
     background-image: url(images/bookmark_folder_xhdpi.png);
   }
   .bookmark-separator {
     background-image: url(images/breadcrumb_xhdpi.png);
   }
 }