[XHR2] content type of blobs passed to send()

[David Flanagan]

I just noticed this in the XHR2 spec:

If data is a Blob
    If the object is of type File and its mediaType attribute is not the empty 
string let mime type be its value.

I think this must reference an out-of-date version of the File spec. 
Currently all Blobs have a type attribute and there is not additional 
type information associated with files.

        David