chromium/third_party/blink/web_tests/external/wpt/focus/support/iframe-activeelement-after-focusing-out-same-site-iframes-outer.html

<!doctype html>
<meta charset="utf-8">
<title>iframe active element after focusing out same site iframes outer</title>
<input></input></br>
<iframe src="iframe-activeelement-after-focusing-out-iframes-inner.html"></iframe>
<script>
let outerlog = "outerlog:";

let input = document.querySelector("input");
let iframe = document.querySelector("iframe");
window.onmessage = function(e) {
  if (e.data == "ready") {
    opener.postMessage("ready", "*");
  } else if (e.data == "focus") {
    outerlog += "willfocusinput,";
    input.focus();
    outerlog += "didfocusinput,";
  } else if (e.data == "getlog") {
    iframe.contentWindow.postMessage("getlog", "*");
  } else {
    opener.postMessage(outerlog + e.data, "*");
  }
};

window.onload = function() {
  window.onfocus = function() {
    outerlog += "windowfocus,";
  };

  window.onblur = function() {
    outerlog += "windowblur,";
  };
};
</script>