Regression in 3.0pre With content_for And Layouts

I just found a regression in a recent commit in the trunk for 3.0 that involves using content_for to help get content in both templates and layouts, a technique described one of Ryan's earliest screen casts. My patch adds a regression test that passes before said commit but is not quite yet in full parity with rails 2.3.4. Could someone please take a look at this and give me some feedback on what else I might be able to do to get these features back?

Commit:
http://github.com/rails/rails/commit/9f5cd0156ab907d8097fc9c588823a9b09038b93

Ticket:
https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/3089-regression-in-30pre-with-content_for-and-layouts