There's a concept of a "complete" main resource error, which is obsolete, since all errors are complete. Also, there's a call sequence of MainResourceLoader -> FrameLoader -> DocumentLoader -> FrameLoader -> DocumentLoader, which can definitely be simplified.
Created attachment 134657 [details] patch
I'm imagining reading this patch in reverse. "Introduce a paramater that's always true..."
Comment on attachment 134657 [details] patch Clearing flags on attachment: 134657 Committed r112599: <http://trac.webkit.org/changeset/112599>
All reviewed patches have been landed. Closing bug.