Add initial auto-roll 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 @@
       match = re.match(r"^## (.+)", line)
       if match:
         current_branch = match.group(1)
         break
     self.Persist("current_branch", current_branch)
 
     # Fetch unfetched revisions.
     if self.Git("svn fetch") is None:
       self.Die("'git svn fetch' failed.")
 
+  def PrepareBranch(self):
     # Get ahold of a safe temporary branch and check it out.
-    if current_branch != self._config[TEMP_BRANCH]:
+    self.RestoreIfUnset("current_branch")
+    if self._state["current_branch"] != self._config[TEMP_BRANCH]:
       self.DeleteBranch(self._config[TEMP_BRANCH])
       self.Git("checkout -b %s" % self._config[TEMP_BRANCH])
 
     # Delete the branch that will be created later if it exists already.
     self.DeleteBranch(self._config[BRANCHNAME])
 
   def CommonCleanup(self):
     self.RestoreIfUnset("current_branch")
     self.Git("checkout -f %s" % self._state["current_branch"])
     if self._config[TEMP_BRANCH] != self._state["current_branch"]:
@@ skipping 57 matching lines @@
 class UploadStep(Step):
   def __init__(self):
     Step.__init__(self, "Upload for code review.")
 
   def RunStep(self):
     print "Please enter the email address of a V8 reviewer for your patch: ",
     reviewer = self.ReadLine()
     args = "cl upload -r \"%s\" --send-mail" % reviewer
     if self.Git(args,pipe=False) is None:
       self.Die("'git cl upload' failed, please try again.")
+
+
+def RunScript(step_classes,
+              config,
+              options,
+              side_effect_handler=DEFAULT_SIDE_EFFECT_HANDLER):
+  state = {}
+  steps = []
+  number = 0
+
+  for step_class in step_classes:
+    # TODO(machenbach): Factory methods.
+    step = step_class()
+    step.SetNumber(number)
+    step.SetConfig(config)
+    step.SetOptions(options)
+    step.SetState(state)
+    step.SetSideEffectHandler(side_effect_handler)
+    steps.append(step)
+    number += 1
+
+  for step in steps[options.s:]:
+    step.Run()