Add a Record button to the web-app if the host supports video recording.

remoting/webapp/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>
 
   <div class="toolbar-border">
 
     <div id="session-status-message"
          i18n-content="LABEL_CONNECTED"></div>
 
     <div id="connected-to"></div>
 
     <div id="new-connection" class="icon-black apps-v2-only">
       <img src="plus.webp" i18n-title="NEW_CONNECTION">
     </div>
 
     <div class="box-spacer"></div>
 
     <button id="toolbar-disconnect"
             type="button"
             i18n-content="DISCONNECT_MYSELF_BUTTON"
             class="apps-v1-only">
     </button>
 
+    <button id="start-stop-recording"
+            type="button"
+            i18n-content="START_STOP_RECORDING" hidden>
+    </button>
+
     <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>
       </ul>
@@ skipping 25 matching lines @@
       </ul>
     </span>
 
   </div>
 
   <div class="toolbar-stub" id="toolbar-stub">
     <div class="arrow-down"></div>
   </div>
 
 </div> <!-- session-toolbar -->