[whatwg] Spec for location object needs to make some properties unforgeable; need supporting WebIDL changes

[Cameron McCormack]

Boris Zbarsky:
> I can live with this, but why is this better than just allowing
> [Unforgeable] on all operations and attributes and defining an "object
> valueOf(); /* returns self */ " on Location?

If we really do want to make all Location interface members be 
unforgeable, then moving the [Unforgeable] up to the interface seems 
like a nicer way to indicate that.  It also means we don't have to 
pretend we really are defining a useful "valueOf" operation.