[css-values] Value of rem when document have no root element #936
Description
It is not specced that what should happen when there is no root element in a document, and one tries to compute value of rem unit.
For example given the following code:
<!DOCTYPE html>
<iframe src="about:blank"></iframe>
<script>
window.onload = function() {
var win = document.querySelector('iframe').contentWindow;
var doc = document.querySelector('iframe').contentDocument;
var b = doc.body;
doc.documentElement.style.fontSize = '24px';
b.style.lineHeight = '2rem';
doc.removeChild(doc.documentElement);
alert('line-height: ' + win.getComputedStyle(b).lineHeight);
};
</script>Gecko and Edge shows 48px, and Blink shows empty.