Turn on git diff copy detection for git-cl upload.

git_cl.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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 import json
@@ skipping 1001 matching lines @@
                     if ': ' in line)
         remote_url = keys.get('URL', None)
     else:
       if cl.GetRemoteUrl() and '/' in cl.GetUpstreamBranch():
         remote_url = (cl.GetRemoteUrl() + '@'
                       + cl.GetUpstreamBranch().split('/')[-1])
   if remote_url:
     upload_args.extend(['--base_url', remote_url])
 
   try:
-    issue, patchset = upload.RealMain(['upload'] + upload_args + args)
+    # upload uses '-C' by default when generating the diff for upload.
+    # Add another '-C' to trigger --find-copies-harder.
+    issue, patchset = upload.RealMain(['upload'] + upload_args + args +
+                                      ['--', '-C'])
   except KeyboardInterrupt:
     sys.exit(1)
   except:
     # If we got an exception after the user typed a description for their
     # change, back up the description before re-raising.
     if change_desc:
       backup_path = os.path.expanduser(DESCRIPTION_BACKUP_FILE)
       print '\nGot exception while uploading -- saving description to %s\n' \
           % backup_path
       backup_file = open(backup_path, 'w')
@@ skipping 72 matching lines @@
     if not options.reviewers and hook_results.reviewers:
       options.reviewers = hook_results.reviewers
 
   # --no-ext-diff is broken in some versions of Git, so try to work around
   # this by overriding the environment (but there is still a problem if the
   # git config key "diff.external" is used).
   env = os.environ.copy()
   if 'GIT_EXTERNAL_DIFF' in env:
     del env['GIT_EXTERNAL_DIFF']
   subprocess2.call(
-      ['git', 'diff', '--no-ext-diff', '--stat', '-M'] + args, env=env)
+      ['git', 'diff', '--no-ext-diff', '--stat', '-C', '-C'] + args, env=env)
 
   if settings.GetIsGerrit():
     return GerritUpload(options, args, cl)
   return RietveldUpload(options, args, cl)
 
 
 def SendUpstream(parser, args, cmd):
   """Common code for CmdPush and CmdDCommit
 
   Squashed commit into a single.
@@ skipping 425 matching lines @@
              'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
   # Not a known command. Default to help.
   GenUsage(parser, 'help')
   return CMDhelp(parser, argv)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))