Support for |change| argument to |GetPreferredTrySlaves()|.

trychange.py

 #!/usr/bin/env python
 # Copyright (c) 2011 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.
 
 """Client-side script to send a try job to the try server. It communicates to
 the try server by either writting to a svn repository or by directly connecting
 to the server by HTTP.
 """
 
@@ skipping 446 matching lines @@
 def GetMungedDiff(path_diff, diff):
   # Munge paths to match svn.
   for i in range(len(diff)):
     if diff[i].startswith('--- ') or diff[i].startswith('+++ '):
       new_file = posixpath.join(path_diff, diff[i][4:]).replace('\\', '/')
       diff[i] = diff[i][0:4] + new_file
   return diff
 
 
 def TryChange(argv,
+              change,
               file_list,
               swallow_exception,
               prog=None,
               extra_epilog=None):
   """
   Args:
     argv: Arguments and options.
     file_list: Default value to pass to --file.
     swallow_exception: Whether we raise or swallow exceptions.
   """
@@ skipping 225 matching lines @@
       options.diff = ''.join(diffs)
 
     if not options.bot:
       # Get try slaves from PRESUBMIT.py files if not specified.
       # Even if the diff comes from options.url, use the local checkout for bot
       # selection.
       try:
         import presubmit_support
         root_presubmit = checkouts[0].ReadRootFile('PRESUBMIT.py')
         options.bot = presubmit_support.DoGetTrySlaves(
+            change,
             checkouts[0].GetFileNames(),
             checkouts[0].checkout_root,
             root_presubmit,
             options.project,
             False,
             sys.stdout)
       except ImportError:
         pass
       # If no bot is specified, either the default pool will be selected or the
       # try server will refuse the job. Either case we don't need to interfere.
@@ skipping 38 matching lines @@
     print >> sys.stderr, e
     return 1
   except (gclient_utils.Error, subprocess2.CalledProcessError), e:
     print >> sys.stderr, e
     return 1
   return 0
 
 
 if __name__ == "__main__":
   fix_encoding.fix_encoding()
-  sys.exit(TryChange(None, [], False))
+  sys.exit(TryChange(None, None, [], False))