Add automatic tag script.

tools/push-to-trunk/common_includes.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 226 matching lines @@
       print data
       print "ERROR: Could not read response. Is your key valid?"
       raise
 
   def Sleep(self, seconds):
     time.sleep(seconds)
 
   def GetDate(self):
     return datetime.date.today().strftime("%Y-%m-%d")
 
+  def GetUTCStamp(self):
+    time.mktime(datetime.datetime.utcnow().timetuple())
+
 DEFAULT_SIDE_EFFECT_HANDLER = SideEffectHandler()
 
 
 class NoRetryException(Exception):
   pass
 
 
 class Step(GitRecipesMixin):
   def __init__(self, text, requires, number, config, state, options, handler):
     self._text = text
@@ skipping 390 matching lines @@
     for (number, step_class) in enumerate(step_classes):
       steps.append(MakeStep(step_class, number, self._state, self._config,
                             options, self._side_effect_handler))
     for step in steps[options.step:]:
       if step.Run():
         return 1
     return 0
 
   def Run(self, args=None):
     return self.RunSteps(self._Steps(), args)