MIME handling of multipart form data isn't working in several cases

[pshaughn]

WPT fetch/api/response/response-consume.html fails several cases by getting "Inappropriate MIME-type for Body" thrown by script/body.rs. The comment at https://github.com/servo/servo/blob/master/components/script/body.rs#L187 is probably relevant.

Other cases are failing on ReadableStream, but this seems entirely disjoint from that.

[CYBAI]

In case there's any code changes to body.rs, just helped to paste its permalink below 👇

servo/components/script/body.rs

Lines 187 to 197 in 64bcce2

	// TODO
	// ... Parser for Mime(TopLevel::Multipart, SubLevel::FormData, _)
	// ... is not fully determined yet.
	if mime.type_() == mime::APPLICATION && mime.subtype() == mime::WWW_FORM_URLENCODED {
	let entries = form_urlencoded::parse(&bytes);
	let formdata = FormData::new(None, root);
	for (k, e) in entries {
	formdata.Append(USVString(k.into_owned()), USVString(e.into_owned()));
	}
	return Ok(FetchedData::FormData(formdata));
	}

[pshaughn]

Right, any one of these issues could stay in the system a long time so I should remember to do that. Thanks.

[pshaughn]

We're using the url crate to parse urlencoded form data; maybe there's just another crate we can use to parse multipart form data? https://docs.rs/multipart/ might work.