Revert of git cl: refactor Changelist codereview detection. (patchset #4 id:60001 of https://codereview.chromium.org/1830923002/ )

Reason for revert:
broke presubmit

Original issue's description:
> git cl: refactor Changelist codereview detection.
> 
> BUG=579160
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=299464

TBR=sergiyb@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=579160,597638

Review URL: https://codereview.chromium.org/1826203003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@299475 0039d316-1c4b-4281-b951-d872f2087c98