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chromium/third_party/blink/web_tests/fast/css/visited-link-href-changed.html 

<!DOCTYPE html>
<style>
a {
    display: block;
    width: 100px;
    height: 100px;
}

a:visited {
    background-color: red;
}

a:link {
    background-color: green;
}

</style>
<p>You should see a green square below.</p>
<a id="link" href=""></a>
<script>
link.offsetTop; // force recalc
link.href = "not-visited.html";
</script>