run_test_cases.py: Enable use of RUN_TEST_CASES_RESULT_FILE as environment variable.

tools/isolate/run_test_cases_test.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.
 
 import logging
 import os
 import sys
 import unittest
 
@@ skipping 81 matching lines @@
   def test_call_timeout_no_kill_eol(self):
     cmd = [sys.executable, SLEEP, '0.001']
     output, code = run_test_cases.call_with_timeout(
         cmd, timeout=100, universal_newlines=True)
     self.assertEquals('Sleeping.\nSlept.\n', output)
     self.assertEquals(0, code)
 
   def test_gtest_filter(self):
     old = run_test_cases.run_test_cases
     exe = os.path.join(ROOT_DIR, 'data', 'gtest_fake', 'gtest_fake_pass.py')
-    def expect(executable, test_cases, jobs, timeout, no_dump):
+    def expect(executable, test_cases, jobs, timeout, result_file):
       self.assertEquals(exe, executable)
       self.assertEquals(['Foo.Bar1', 'Foo.Bar3'], test_cases)
       self.assertEquals(run_test_cases.num_processors(), jobs)
       self.assertEquals(120, timeout)
-      self.assertEquals(None, no_dump)
+      self.assertEquals(exe + '.run_test_cases', result_file)
       return 89
     try:
       run_test_cases.run_test_cases = expect
       result = run_test_cases.main([exe, '--gtest_filter=Foo.Bar*-*.Bar2'])
       self.assertEquals(89, result)
     finally:
       run_test_cases.run_test_cases = old
 
 
 class WorkerPoolTest(unittest.TestCase):
@@ skipping 18 matching lines @@
         pool.join()
         self.fail()
     except FearsomeException:
       self.assertEquals(True, task_added)
 
 
 if __name__ == '__main__':
   VERBOSE = '-v' in sys.argv
   logging.basicConfig(level=logging.DEBUG if VERBOSE else logging.ERROR)
   unittest.main()