If you do that kind of rebase you have to force-push to your branch, and that's not great for many reasons. The other option is to `git merge chromium/master` into your fork. This way you don't have to force-push, but the history is not that clean and bisecting can be tricky.
Ah true didn't think of that, as I've never worked on such large projects were force pushing becomes a problem.
But with manually editing .patch files you need to manually find out how to resolve the conflicts, while in a rebase git at least shows you the merge conflicts.