Change default ReportErrorFileAndLine to use filename:lineno format.

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 2035 matching lines @@
     input_api1.FilterSourceFile = lambda x: x
     input_api1.AffectedFiles = test
     self.mox.ReplayAll()
 
     results1 = presubmit_canned_checks.CheckChangeHasNoTabs(input_api1,
         presubmit.OutputApi, None)
     self.assertEquals(len(results1), 1)
     self.assertEquals(results1[0].__class__,
         presubmit.OutputApi.PresubmitPromptWarning)
     self.assertEquals(results1[0]._long_text,
-        'makefile.foo, line 46')
+        'makefile.foo:46')
 
   def testCannedCheckLongLines(self):
     check = lambda x, y, z: presubmit_canned_checks.CheckLongLines(x, y, 10, z)
     self.ContentTest(check, '0123456789', None, '01234567890', None,
                      presubmit.OutputApi.PresubmitPromptWarning)
 
   def testCannedCheckJavaLongLines(self):
     check = lambda x, y, _: presubmit_canned_checks.CheckLongLines(x, y, 80)
     self.ContentTest(check, 'A ' * 50, 'foo.java', 'A ' * 50 + 'B', 'foo.java',
                      presubmit.OutputApi.PresubmitPromptWarning)
@@ skipping 657 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()