Move statistical functions in bisect script to their own module.

tools/run-bisect-perf-regression.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 """Run Performance Test Bisect Tool
 
 This script is used by a trybot to run the src/tools/bisect-perf-regression.py
 script with the parameters specified in run-bisect-perf-regression.cfg. It will
 check out a copy of the depot in a subdirectory 'bisect' of the working
 directory provided, and run the bisect-perf-regression.py script there.
+
 """
 
+import imp
 import optparse
 import os
 import platform
 import subprocess
 import sys
 import traceback
 
 from auto_bisect import bisect_utils
 
-# Special import required because of dashes in file name.
-bisect = __import__('bisect-perf-regression')
+bisect = imp.load_source('bisect-perf-regression',
+    os.path.join(os.path.abspath(os.path.dirname(sys.argv[0])),
+        'bisect-perf-regression.py'))
+
 
 CROS_BOARD_ENV = 'BISECT_CROS_BOARD'
 CROS_IP_ENV = 'BISECT_CROS_IP'
 
 # Default config file names.
 BISECT_REGRESSION_CONFIG = 'run-bisect-perf-regression.cfg'
 RUN_TEST_CONFIG = 'run-perf-test.cfg'
 WEBKIT_RUN_TEST_CONFIG = os.path.join(
     '..', 'third_party', 'WebKit', 'Tools', 'run-perf-test.cfg')
 
 class Goma(object):
-  """Convenience class to start and stop goma."""
 
   def __init__(self, path_to_goma):
     self._abs_path_to_goma = None
     self._abs_path_to_goma_file = None
     if not path_to_goma:
       return
     self._abs_path_to_goma = os.path.abspath(path_to_goma)
     filename = 'goma_ctl.bat' if os.name == 'nt' else 'goma_ctl.sh'
     self._abs_path_to_goma_file = os.path.join(self._abs_path_to_goma, filename)
 
@@ skipping 35 matching lines @@
     self._Stop()
 
     if subprocess.call([self._abs_path_to_goma_file, 'start']):
       raise RuntimeError('Goma failed to start.')
 
   def _Stop(self):
     subprocess.call([self._abs_path_to_goma_file, 'stop'])
 
 
 def _LoadConfigFile(config_file_path):
-  """Loads to given file as a python module and returns the config dictionary.
+  """Loads the given file as a python module and returns the config dictionary.
 
   The config file is loaded as a Python module.
 
   Args:
     config_file_path: Path to the config file.
 
   Returns:
     If successful, returns the config dict loaded from the file. If no
     such dictionary could be loaded, returns the empty dictionary.
   """
@@ skipping 445 matching lines @@
           config, current_dir, opts.path_to_goma)
 
   print ('Error: Could not load config file. Double check your changes to '
          'run-bisect-perf-regression.cfg or run-perf-test.cfg for syntax '
          'errors.\n')
   return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())