Workaround older python versions' less capable tarfile.

tools/export_tarball/export_tarball.py

 #!/usr/bin/python
 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This tool creates a tarball with all the sources, but without .svn directories.
 
 It can also remove files which are not strictly required for build, so that
 the resulting tarball can be reasonably small (last time it was ~110 MB).
@@ skipping 20 matching lines @@
     'third_party/lighttpd',
     'third_party/WebKit/LayoutTests',
     'webkit/data/layout_tests',
     'webkit/tools/test/reference_build',
 )
 
 def GetSourceDirectory():
   return os.path.realpath(
     os.path.join(os.path.dirname(__file__), '..', '..', '..', 'src'))
 
+# Workaround lack of the exclude parameter in add method in python-2.4.
+# TODO(phajdan.jr): remove the workaround when it's not needed on the bot.
+class MyTarFile(tarfile.TarFile):
+  def add(self, name, arcname=None, recursive=True, exclude=None):
+    if exclude is not None and exclude(name):
+      return
+    tarfile.TarFile.add(self, name, arcname=arcname, recursive=recursive)
+
 def main(argv):
   parser = optparse.OptionParser()
   parser.add_option("--remove-nonessential-files",
                     dest="remove_nonessential_files",
                     action="store_true", default=False)
 
   options, args = parser.parse_args(argv)
 
   if len(args) != 1:
     print 'You must provide only one argument: output file name'
@@ skipping 13 matching lines @@
       return True
 
     if not options.remove_nonessential_files:
       return False
     for nonessential_dir in NONESSENTIAL_DIRS:
       if path.startswith(os.path.join(GetSourceDirectory(), nonessential_dir)):
         return True
 
     return False
 
-  archive = tarfile.open(output_fullname, 'w:bz2')
+  archive = MyTarFile.open(output_fullname, 'w:bz2')
   try:
     archive.add(GetSourceDirectory(), arcname=output_basename,
                 exclude=ShouldExcludePath)
   finally:
     archive.close()
 
   return 0
 
 if __name__ == "__main__":
   sys.exit(main(sys.argv[1:]))