Added separate checkout and config file generation to bisect script

tools/run-bisect-perf-regression.py

Index: tools/run-bisect-perf-regression.py
diff --git a/tools/run-bisect-perf-regression.py b/tools/run-bisect-perf-regression.py
new file mode 100755
index 0000000000000000000000000000000000000000..120e407a020b7703cb628bdfa2b5e704f2f55714
--- /dev/null
+++ b/tools/run-bisect-perf-regression.py
@@ -0,0 +1,100 @@
+#!/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 subprocess
+import sys
+
+
+def LoadConfigFile():
+  """Attempts to load the file 'run-bisect-perf-regression.cfg' as a module
+  and grab the global config dict.
+
+  Returns:
+    The config dict which should be formatted as follows:
+    {'command': string, 'good_revision': string, 'bad_revision': string
+     'metric': string}.
+    Returns None on failure.
+  """
+  try:
+    local_vars = {}
+    execfile('run-bisect-perf-regression.cfg', local_vars)
+
+    return local_vars['config']
+  except:
+    return None
+
+
+def RunBisectionScript(config, working_directory):
+  """Attempts to execute src/tools/bisect-perf-regression.py with the parameters
+  passed in.
+
+  Args:
+    config: A dict containing the parameters to pass to the script.
+
+  Returns:
+    0 on success, otherwise 1.
+  """
+
+  cmd = ['python', 'bisect-perf-regression.py',
+         '-c', config['command'],
+         '-g', config['good_revision'],
+         '-b', config['bad_revision'],
+         '-m', config['metric'],
+         '--working_directory', working_directory,
+         '--output_buildbot_annotations']
+
+  return_code = subprocess.call(cmd)
+
+  if return_code:
+    print 'Error: bisect-perf-regression.py returned with error %d' %\
+        return_code
+    print
+
+  return return_code
+
+
+def main():
+
+  usage = ('%prog [options] [-- chromium-options]\n'
+           'Used by a trybot to run the bisection script using the parameters'
+           ' provided in the run-bisect-perf-regression.cfg file.')
+
+  parser = optparse.OptionParser(usage=usage)
+  parser.add_option('-w', '--working_directory',
+                    type='str',
+                    help='A working directory to supply to the bisection '
+                    'script, which will use it as the location to checkout '
+                    'a copy of the chromium depot.')
+  (opts, args) = parser.parse_args()
+
+  if not opts.working_directory:
+    print 'Error: missing required parameter: --working_directory'
+    print
+    parser.print_help()
+    return 1
+
+  config = LoadConfigFile()
+  if not config:
+    print 'Error: Could not load config file.'
+    print
+    return 1
+
+  return RunBisectionScript(config, opts.working_directory)
+
+
+if __name__ == '__main__':
+  sys.exit(main())