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chromium/third_party/blink/web_tests/fast/events/touch/gesture/resources/drag-inside-nested-iframes2.html 

<html>
<style>
  iframe {
    height: 200px;
    width: 200px;
    overflow: hidden;
  }
</style>
<body>
<iframe src="drag-inside-nested-iframes3.html"></iframe>
<script>
  document.addEventListener('contextmenu', event => {
    event.preventDefault();
  });
</script>
</body>
</html>