@misty And that's the second fork.
The original Chromium was based on a fork, then they got it merged upstream but there was still a lot that was just conditionally compiled so that there were some features only used by Chrome (for instance, it had an entirely different JavaScript engine) and some used only by the other WebKit ports.
After a while where they were maintained in one codebase but with a lot of ifdefs and divergence and conflict, they eventually forked again.