Reland "Maintain change log file directly on trunk branch in push-to-trunk."

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 293 matching lines @@
 
 
 class ApplyChanges(Step):
   MESSAGE = "Apply squashed changes."
 
   def RunStep(self):
     self.ApplyPatch(self.Config(PATCH_FILE))
     Command("rm", "-f %s*" % self.Config(PATCH_FILE))
 
 
+class AddChangeLog(Step):
+  MESSAGE = "Add ChangeLog changes to trunk branch."
+
+  def RunStep(self):
+    # The change log has been modified by the patch. Reset it to the version
+    # on trunk and apply the exact changes determined by this PrepareChangeLog
+    # step above.
+    self.GitCheckoutFile(self.Config(CHANGELOG_FILE))
+    changelog_entry = FileToText(self.Config(NEW_CHANGELOG_FILE))
+    old_change_log = FileToText(self.Config(CHANGELOG_FILE))
+    new_change_log = "%s\n\n\n%s" % (changelog_entry, old_change_log)
+    TextToFile(new_change_log, self.Config(CHANGELOG_FILE))
+    os.remove(self.Config(NEW_CHANGELOG_FILE))
+
+
 class SetVersion(Step):
   MESSAGE = "Set correct version for trunk."
 
   def RunStep(self):
     output = ""
     for line in FileToText(self.Config(VERSION_FILE)).splitlines():
       if line.startswith("#define MAJOR_VERSION"):
         line = re.sub("\d+$", self["major"], line)
       elif line.startswith("#define MINOR_VERSION"):
         line = re.sub("\d+$", self["minor"], line)
@@ skipping 198 matching lines @@
       PrepareChangeLog,
       EditChangeLog,
       IncrementVersion,
       CommitLocal,
       UploadStep,
       CommitRepository,
       StragglerCommits,
       SquashCommits,
       NewBranch,
       ApplyChanges,
+      AddChangeLog,
       SetVersion,
       CommitTrunk,
       SanityCheck,
       CommitSVN,
       TagRevision,
       CheckChromium,
       SwitchChromium,
       UpdateChromiumCheckout,
       UploadCL,
       SwitchV8,
       CleanUp,
     ]
 
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(PushToTrunk(CONFIG).Run())