Add retry feature for push-to-trunk script.

tools/push-to-trunk/push_to_trunk.py

 #!/usr/bin/env python
 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
@@ skipping 84 matching lines @@
   def Reload(self, body):
     """Attempts to reload the commit message from rietveld in order to allow
     late changes to the LOG flag. Note: This is brittle to future changes of
     the web page name or structure.
     """
     match = re.search(r"^Review URL: https://codereview\.chromium\.org/(\d+)$",
                       body, flags=re.M)
     if match:
       cl_url = "https://codereview.chromium.org/%s/description" % match.group(1)
       try:
-        body = self.ReadURL(cl_url)
+        # Fetch from Rietveld but only retry once with one second delay since
+        # there might be many revisions.
+        body = self.ReadURL(cl_url, wait_plan=[1])
       except urllib2.URLError:
         pass
     return body
 
   def RunStep(self):
     self.RestoreIfUnset("last_push")
 
     # These version numbers are used again later for the trunk commit.
     self.ReadAndPersistVersion()
 
@@ skipping 454 matching lines @@
 def Main():
   parser = BuildOptions()
   (options, args) = parser.parse_args()
   if not ProcessOptions(options):
     parser.print_help()
     return 1
   RunPushToTrunk(CONFIG, options)
 
 if __name__ == "__main__":
   sys.exit(Main())