To be called with a cron job.

TEST=tools/push-to-trunk/auto_roll.py

TODO: Add a revision filter to allow "MIPS" related changes to take over the lkgr.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/70373002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17833 ce2b1a6d-e550-0410-aec6-3dcde31c8c00