There was a small unfortunate bug in the "git cl format" implementation that essentially transformed the command into a no-op. :-(
The issue has been fixed and submitted, and you should get the correct version on you next "gclient" or "update_depot_tools" call.
Happy auto-reformatting to everyone :-)
- Digit
PS: As a reminder, the tool at the moment only works on Linux and Darwin at the moment, and requires clang-format being installed under /usr/lib/.