Add NOEXPORT=true commit message whenever import script is run.

third_party/WebKit/Tools/Scripts/webkitpy/w3c/deps_updater_unittest.py

 # Copyright 2016 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.
 
 import unittest
 
 from webkitpy.common.host_mock import MockHost
 from webkitpy.common.system.executive_mock import MockExecutive
 from webkitpy.w3c.deps_updater import DepsUpdater
 
@@ skipping 57 matching lines @@
         updater._has_changes = lambda: True
         updater._commit_changes('dummy message')
         self.assertEqual(
             host.executive.calls,
             [['git', 'commit', '--all', '-F', '-']])
 
     def test_commit_message(self):
         updater = DepsUpdater(MockHost())
         self.assertEqual(
             updater._commit_message('aaaa', '1111'),
-            'Import 1111\n\nUsing update-w3c-deps in Chromium aaaa.\n\n')
+            'Import 1111\n\n'
+            'Using update-w3c-deps in Chromium aaaa.\n\n'
+            'NOEXPORT=true')
 
     def test_cl_description_with_empty_environ(self):
         host = MockHost()
         host.executive = MockExecutive(output='Last commit message\n')
         updater = DepsUpdater(host)
         description = updater._cl_description()
         self.assertEqual(
             description,
             ('Last commit message\n'
              'TBR=qyearsley@chromium.org\n'
@@ skipping 40 matching lines @@
                     '--work',
                     '--tests-root',
                     '/mock-checkout/third_party/WebKit/LayoutTests/external/wpt'
                 ],
                 [
                     'git',
                     'add',
                     '/mock-checkout/third_party/WebKit/LayoutTests/external/wpt/MANIFEST.json'
                 ]
             ])