Correctly overwrite author in chromium roll script.

tools/push-to-trunk/git_recipes.py

 #!/usr/bin/env python
 # Copyright 2014 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 149 matching lines @@
     if force:
       args.append("-f")
     if cq:
       args.append("--use-commit-queue")
     if bypass_hooks:
       args.append("--bypass-hooks")
     # TODO(machenbach): Check output in forced mode. Verify that all required
     # base files were uploaded, if not retry.
     self.Git(MakeArgs(args), pipe=False)
 
-  def GitCommit(self, message="", file_name=""):
+  def GitCommit(self, message="", file_name="", author=None):
     assert message or file_name
     args = ["commit"]
     if file_name:
       args += ["-aF", Quoted(file_name)]
     if message:
       args += ["-am", Quoted(message)]
+    if author:
+      args += ["--author", "\"%s <%s>\"" % (author, author)]
     self.Git(MakeArgs(args))
 
   def GitPresubmit(self):
     self.Git("cl presubmit", "PRESUBMIT_TREE_CHECK=\"skip\"")
 
   def GitDCommit(self):
     self.Git("cl dcommit -f --bypass-hooks", retry_on=lambda x: x is None)
 
   def GitDiff(self, loc1, loc2):
     return self.Git(MakeArgs(["diff", loc1, loc2]))
@@ skipping 34 matching lines @@
   @Strip
   def GitSVNFindSVNRev(self, git_hash, branch=""):
     return self.Git(MakeArgs(["svn find-rev", git_hash, branch]))
 
   def GitSVNDCommit(self):
     return self.Git("svn dcommit 2>&1", retry_on=lambda x: x is None)
 
   def GitSVNTag(self, version):
     self.Git(("svn tag %s -m \"Tagging version %s\"" % (version, version)),
              retry_on=lambda x: x is None)