viewport-percentage-compute-with-scrollbars.html

<!DOCTYPE html>
<html>
    <body>
        <div id="outer" style="height: 50vh; width: 50vw; background-color: lightcyan; border: solid 1px black; padding: 25px; margin: 25px;overflow:auto;" >
	    <div id="inner" style="width: 30%; height: 50%; background-color: lightseagreen; border: solid 1px black;overflow:auto; margin: 5px;"> 
                <div id="fixed-block" style="height:500px;"> </div>
	    </div>
            <div id="fixed-block" style="height:500px; border: solid 1px black"> </div>
        </div>
    </body>
</html>

chromium/third_party/blink/web_tests/fast/css/viewport-percentage-compute-with-scrollbars.html