<style>
*{
    -webkit-mask-image:none,none,url(x);
}
</style>
<p style="position:absolute; top: -1000px">https://bugs.webkit.org/show_bug.cgi?id=50151 : Crash in LayoutBox::paintMaskImages due to a mask without an associated image<br>
The test passes if it does not CRASH (normally the output is a white page)</p>