[cssom] location should be a URL

[annevk]

It seems to me that https://drafts.csswg.org/cssom-1/#concept-css-style-sheet-location should be a URL and serialized when returned to script.

[GPHemsley]

The "location" state item is defined as:

Specified when created. The absolute-URL string of the first request of the CSS style sheet or null if the CSS style sheet was embedded. Does not change during the lifetime of the CSS style sheet.

This includes a link to the URL spec.

Is this more an issue of how it's represented programmatically than definitionally?

The StyleSheet Interface represents href as USVString?.

The spec defines serialize a URL and also invokes URL's URL serializer for location in multiple places.