I don't know for sure. I was using mod_perl2, when I adopted Apache2, even though libapreq2 was in beta, ( and because of that so was mod_perl2. But because of the wording of this:

Apache2::Cookie::fetch now expects an $r object as (second) argument, although this isn't necessary in mod_perl 2 if Apache2::RequestUtil is loaded and 'PerlOptions +GlobalRequest' is in effect.

I would say Apache2::Cookie is the right module.