In Rails 3 the only way to get for content captured with the
content_for method in a view is to call yield from within a view.
However, sometimes is it useful to get to this data from within a
helper (for instance to provide a default value). Calling yield from
within the helper method won't work, and accessing the @_content_for
variable directly is not encouraged.
Proposed solution: add a captured_content_for method so helper methods
can legitimately access captured content. Add to /action_pack/lib/
# Get content previously captured with +content_for+. This is the
same as calling
# +yield+ inside a template except that this method can be used
inside helper methods.
Lighthouse ticket: https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/4537