<!doctype html>
<html>
    <head>
        <title>Viewport: Resize Event On Showing Iframe</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, minimum-scale=1">
        <script src="/resources/testharness.js"></script>
        <script src="/resources/testharnessreport.js"></script>
        <script>
          async_test(t => {
            document.addEventListener("DOMContentLoaded", () => {
              let iframe = document.querySelector("iframe");
            