<!DOCTYPE html>
<html>
<body>
<p>This frame should have a blue background.</p>
<iframe></iframe>
<script>
if (window.testRunner)
    testRunner.waitUntilDone();
var html = `
<style>
body { 
  background: blue; 
}
</style>
`;
var iframe = document.querySelector("iframe");
iframe.onload = () => {
    if (window.testRunner)
        testRunner.notifyDone();
};
iframe.srcdoc = html;
</script>
</body>
</html>