LayoutTests/media/ios/autoplay-only-in-main-document.html

<meta name="viewport" content="width=device-width">
<style>
iframe {
    width: 300px;
    height: 200px;
}
</style>
<script>
if (window.testRunner) {
    internals.settings.setVideoPlaybackRequiresUserGesture(true);
    testRunner.waitUntilDone();
    testRunner.dumpAsText();
}

var iframe;

function testVideo() {
    var doc = iframe.contentDocument;
    var video = doc.querySelector("video");

    var result = document.createElement("p");
    if (video.paused && !video.ended)
        result.textContent = "PASS: Video did not autoplay";
    else
        result.textContent = "FAIL: Video was autoplaying";
    
    document.body.appendChild(result);

    if (window.testRunner)
        testRunner.notifyDone();
}

window.addEventListener("load", function () {
    iframe = document.querySelector("iframe");
    iframe.addEventListener("load", testVideo, false);
    iframe.src = "../content/test.mp4";
}, false);

</script>
<iframe></iframe>