 in iframe.
</h4>
<iframe srcdoc="<p>Hello, world!</p>"></iframe>
<script>
  async_test(t => {
    window.onload = () => {
      const iframe = document.querySelector("iframe");

      let resize_event_count = 0;
      iframe.contentWindow.visualViewport.addEventListener("resize", () => {
        resize_event_count++;
      });

      const originalVisualViewportWidth = iframe.contentWindow.visualViewport.width;

      iframe.contentDocument.body.style.height = "10000px";
      // Force layout to queue a re