Re: Removing 'caller' from WebIDL

I agree that we shouldn't be proliferating the use of callers any 
further than what is necessary for compatibility.  I don't think it 
would be any/much of a burden to have a callable collection class for 
document.all (and whichever other ones need it) and a non-callable one 
for the rest, including new collections.

I'm open to removing "caller" from Web IDL if people think that's best, 
and I'd be happy to suggest wording to be added to the HTML spec to 
handle the cases that do need to remain.