Fix depot_tools presubmit check for ubuntu 12.04.

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 1574 matching lines @@
 
     self.mox.ReplayAll()
 
     results1 = check(input_api1, presubmit.OutputApi, None)
     self.assertEquals(results1, [])
     results2 = check(input_api2, presubmit.OutputApi, None)
     self.assertEquals(len(results2), 1)
     self.assertEquals(results2[0].__class__, error_type)
 
   def ReadFileTest(self, check, content1, content2, error_type):
-    self.mox.StubOutWithMock(presubmit.InputApi, 'ReadFile')
     change1 = presubmit.Change(
         'foo1', 'foo1\n', self.fake_root_dir, None, 0, 0, None)
     input_api1 = self.MockInputApi(change1, False)
     affected_file1 = self.mox.CreateMock(presubmit.SvnAffectedFile)
     input_api1.AffectedSourceFiles(None).AndReturn([affected_file1])
     input_api1.ReadFile(affected_file1, 'rb').AndReturn(content1)
     change2 = presubmit.Change(
         'foo2', 'foo2\n', self.fake_root_dir, None, 0, 0, None)
     input_api2 = self.MockInputApi(change2, False)
     affected_file2 = self.mox.CreateMock(presubmit.SvnAffectedFile)
@@ skipping 873 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()