Update from chromium https://crrev.com/304586

build/util/lastchange.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """
 lastchange.py -- Chromium revision fetching utility.
 """
 
 import re
@@ skipping 90 matching lines @@
   """
   hsh = ''
   proc = RunGitCommand(directory, ['rev-parse', 'HEAD'])
   if proc:
     output = proc.communicate()[0].strip()
     if proc.returncode == 0 and output:
       hsh = output
   if not hsh:
     return None
   pos = ''
-  proc = RunGitCommand(directory, ['show', '-s', '--format=%B', 'HEAD'])
+  proc = RunGitCommand(directory, ['cat-file', 'commit', 'HEAD'])
   if proc:
     output = proc.communicate()[0]
     if proc.returncode == 0 and output:
       for line in reversed(output.splitlines()):
         if line.startswith('Cr-Commit-Position:'):
           pos = line.rsplit()[-1].strip()
   if not pos:
     return VersionInfo('git', hsh)
   return VersionInfo('git', '%s-%s' % (hsh, pos))
 
@@ skipping 168 matching lines @@
       if header:
         WriteIfChanged(header,
                        GetHeaderContents(header, opts.version_macro,
                                          version_info.revision))
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())