chromium/third_party/blink/web_tests/editing/selection/4975120.html

<head>
<script>
if (window.testRunner)
    testRunner.waitUntilDone();

function runTest() {
    var input = document.getElementById("input");
    input.setSelectionRange(0, 3);
    input.focus();
    var frame = frames[0];
    frame.focus();
    frame.getSelection().collapse(frame.document.body, 0);
    
    if (!window.testRunner)
        return;

    testRunner.setWindowFocus(false);
    testRunner.setWindowFocus(true);
    testRunner.notifyDone();
}
</script>
</head>
<body>
  <p>This tests for a bug that caused the parent of an active frame to paint as
    though it were active when its window becomes key.  To run manually, make
    another window active and then make this window active. Only the subframe
    should appear active.</p>
  <input id="input" type="text" value="foo"><br>
  <iframe src="../resources/contenteditable-iframe-src.html" onload="runTest()">
  </iframe>
</body>

<script>
</script>