Output a list of suggested OWNERS reviewers when needed.

tests/presubmit_unittest.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Unit tests for presubmit_support.py and presubmit_canned_checks.py."""
 
 # pylint: disable=E1101,E1103
 
 import logging
@@ skipping 2211 matching lines @@
       else:
         people = reviewers
 
       if issue:
         input_api.rietveld.get_issue_properties(
             int(input_api.change.issue), True).AndReturn(rietveld_response)
         people.add(owner_email)
 
       fake_db.directories_not_covered_by(set(['foo/xyz.cc']),
           people).AndReturn(uncovered_dirs)
+      if not is_committing and uncovered_dirs:
+        fake_db.reviewers_for(set(['foo/xyz.cc'])).AndReturn(owner_email)
 
     self.mox.ReplayAll()
     output = presubmit.PresubmitOutput()
     results = presubmit_canned_checks.CheckOwners(input_api,
         presubmit.OutputApi)
     if results:
       results[0].handle(output)
     self.assertEquals(output.getvalue(), expected_output)
 
   def testCannedCheckOwners_Approved(self):
@@ skipping 211 matching lines @@
         owners_check=False)
     self.assertEqual(1, len(results))
     self.assertEqual(
         'Found line ending with white spaces in:', results[0]._message)
     self.checkstdout('')
 
 
 if __name__ == '__main__':
   import unittest
   unittest.main()