<!DOCTYPE html> <!-- webkit-test-runner [ LayoutFormattingContextEnabled=true LayoutFormattingContextIntegrationEnabled=false ] -->
<html>
<body>
    <div style="margin: 20px; width: 20px; height: 20px;">
        <div style="margin-top: 20px; width: 20px; height: 20px;"></div>
    </div>
</body>
</html>