Add a menu option for the right-hand Ctrl -> Meta mapping.

remoting/webapp/crd/html/toolbar.html

 <!--
 Copyright (c) 2014 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.
 -->
 <div id="session-toolbar"
      data-ui-mode="in-session"
      class="toolbar-container apps-v1-only"
      hidden>
 
@@ skipping 18 matching lines @@
 
     <span class="menu-button" id="send-keys-menu">
       <button class="menu-button-activator">
         <span i18n-content="SEND_KEYS"></span>
         <img src="disclosure_arrow_down.webp"
              class="kd-disclosureindicator">
       </button>
       <ul>
         <li id="send-ctrl-alt-del" i18n-content="SEND_CTRL_ALT_DEL"></li>
         <li id="send-print-screen" i18n-content="SEND_PRINT_SCREEN"></li>
+        <li id="map-right-ctrl-to-meta" i18n-content="MAP_RIGHT_CTRL_TO_META">
+        </li>
       </ul>
     </span>
 
     <span class="menu-button" id="screen-options-menu">
       <button class="menu-button-activator">
         <span i18n-content="SCREEN_OPTIONS"></span>
         <img src="disclosure_arrow_down.webp"
              class="kd-disclosureindicator">
       </button>
       <ul>
@@ skipping 16 matching lines @@
       </ul>
     </span>
 
   </div>
 
   <div class="toolbar-stub" id="toolbar-stub">
     <div class="arrow-down"></div>
   </div>
 
 </div> <!-- session-toolbar -->