guest_with_select.html | Explore in Territory

<body>
  <style>
    .small-select {
      position: fixed;
      left: 0px;
      top: 0px;
      width: 20px;
      height: 10px;
      font-size: 6px;
    }
  </style>
  <select class="small-select">
    <option value="Option1"> Option 1</option>
  </select>
  <script>
  window.addEventListener('load', function() {
    var select = document.querySelector('select');

    select.addEventListener('mousedown', function() {
      chrome.test.sendMessage('CLICK');
    });

    select.value = 'NOT_SELECTED';
  });
  </script>
</body>

chromium/chrome/test/data/extensions/platform_apps/web_view/shim/guest_with_select.html