Fixing Windows buildbot exception.

tools/testing/perf_testing/create_graph.py

 #!/usr/bin/python
 
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 import datetime
 import math
 from matplotlib.font_manager import FontProperties
 import matplotlib.pyplot as plt
@@ skipping 89 matching lines @@
     os.chmod(path, stat.S_IWRITE)
     os.unlink(path)
   # TODO(efortuna): building the sdk locally is a band-aid until all build
   # platform SDKs are hosted in Google storage. Pull from https://sandbox.
   # google.com/storage/?arg=dart-dump-render-tree#dart-dump-render-tree%2Fsdk
   # eventually.
   # TODO(efortuna): Currently always building ia32 architecture because we don't
   # have test statistics for what's passing on x64. Eliminate arch specification
   # when we have tests running on x64, too.
   shutil.rmtree(os.path.join(os.getcwd(), 
-    utils.GetBuildRoot(utils.GuessOS(), 'release', 'ia32')), onerror=on_rm_error)
+      utils.GetBuildRoot(utils.GuessOS(), 'release', 'ia32')), 
+      onerror=on_rm_error)
   lines = run_cmd([os.path.join('.', 'tools', 'build.py'), '-m', 'release',
-    '--arch=ia32', 'create_sdk'])
+      '--arch=ia32', 'create_sdk'])
   
   for line in lines:
     if 'BUILD FAILED' in lines:
       # Someone checked in a broken build! Just stop trying to make it work
       # and wait to try again.
       print 'Broken Build'
       return 1
   return 0
 
 def ensure_output_directory(dir_name):
@@ skipping 621 matching lines @@
       if has_new_code():
         run_test_sequence(cl, size, language, perf)
       else:
         time.sleep(SLEEP_TIME)
   else:
     run_test_sequence(cl, size, language, perf)
 
 if __name__ == '__main__':
   main()