The slowest part of `git webkit pr`, if you haven't pushed a PR for a while, is updating the fork by pushing from my local repo, which can be slow on connections with slow upload. There's a --verbose log for this, but I think it should always log so I know what's causing the delay.
The last thing logged before the long delay is `Total errors found: 0 in 3 files`
*** This bug has been marked as a duplicate of bug 242801 ***
Un-duped since this bug has to do with logging while pushing.