chrome/browser/resources/net_internals/sockets_view.html

<style>
#sockets-view-close-idle-button,
#sockets-view-flush-button {
  margin-bottom: 2px;
}
</style>

<div id=sockets-view-tab-content class=content-box>
  <ul style='margin-top:0'>
    <li>
      <input type=button value="Close idle sockets" id=sockets-view-close-idle-button>
    </li>
    <li>
      <input type=button value="Flush socket pools" id=sockets-view-flush-button>
      <span class=warning-text>May break pages with active connections</span>
    </li>
  </ul>
</div>