Make git-cl work with OWNERS files in a non .git/hooks/pre-cl-* world

presubmit_canned_checks.py

 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 ### Description checks
 
 def CheckChangeHasTestField(input_api, output_api):
   """Requires that the changelist have a TEST= field."""
@@ skipping 608 matching lines @@
       out.append('%s has %d build(s) pending' %
                   (builder_name, pending_builds_len))
   if out:
     return [output_api.PresubmitPromptWarning(
         'Build(s) pending. It is suggested to wait that no more than %d '
             'builds are pending.' % max_pendings,
         long_text='\n'.join(out))]
   return []
 
 
-def CheckOwners(input_api, output_api, source_file_filter=None):
+def CheckOwners(input_api, output_api, email_regexp=None,
+    source_file_filter=None):
   affected_files = set([f.LocalPath() for f in
       input_api.change.AffectedFiles(source_file_filter)])
   owners_db = input_api.owners_db
+  if email_regexp:
+    owners_db.email_regexp = input_api.re.compile(email_regexp)
 
   if input_api.is_committing and input_api.tbr:
     return [output_api.PresubmitNotifyResult(
         '--tbr was specified, skipping OWNERS check')]
   elif input_api.is_committing:
     approvers = _Approvers(input_api, owners_db.email_regexp)
     missing_files = owners_db.files_not_covered_by(affected_files, approvers)
     if missing_files:
       return [output_api.PresubmitError('Missing LGTM from an OWNER for: %s' %
               ','.join(missing_files))]
@@ skipping 22 matching lines @@
   # redundant (since the commit queue also enforces the presubmit checks).
   def match_reviewer(r):
     return email_regexp.match(r) and not input_api.re.match(owner, r)
 
   approvers = []
   for m in issue_props['messages']:
     if 'lgtm' in m['text'].lower() and match_reviewer(m['sender']):
       approvers.append(m['sender'])
   return set(approvers)