chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/negative-flex-margins-crash.html

<!DOCTYPE html>
<title>CSS Flexbox: Crash caused by negative width in flex box</title>
<link rel="author" title="Christian Biesinger" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#box-model">
<link rel="issue" href="https://crbug.com/490423">
<meta name="assert" content="Check that crash doesn't happen in flex box with negative margin.">

<style>
div {
  display: flex;
}

.inner {
  margin-left: -4em;
}
</style>
<div>
    <div>
        <div class="inner">PASS if we don't assert</div>
    </div>
</div>