chromium/third_party/blink/web_tests/fast/frames/unique-name-main-frame-conflict.html

<!DOCTYPE html>
<html>
<head>
<script>
function runTest()
{
    if (window.testRunner) {
        testRunner.dumpAsText();
        testRunner.dumpChildFrames();
    }
    // Before https://crrev.com/1968213002 main frame's unique name would be
    // set without any checks for conflicts with names of subframes.
    //
    // Note that layout tests do not include the name of the main frame
    // in test output - this means that the test verification of uniqueness
    // depends on the assert in FrameTree::setUniqueName (which should make
    // this test crash if the main frame's unique name is not truly unique).
    window.name = "subframeName";
}
</script>
</head>
<body onload="runTest()">
<iframe name="subframeName"></iframe>
</body>
</html>