Add --issue flag to git cl status.

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 and Gerrit."""
 
 from __future__ import print_function
@@ skipping 3260 matching lines @@
     - Green    LGTM'ed
     - Magenta  in the commit queue
     - Cyan     was committed, branch can be deleted
 
   Also see 'git cl comments'.
   """
   parser.add_option('--field',
                     help='print only specific field (desc|id|patch|status|url)')
   parser.add_option('-f', '--fast', action='store_true',
                     help='Do not retrieve review status')
+  parser.add_option('-i', '--issue', type=int,
+                    help='Operate on this issue number instead of the current'
+                      ' branch\'s implicit issue. Only valid with --field.')
   parser.add_option(
       '-j', '--maxjobs', action='store', type=int,
       help='The maximum number of jobs to use when retrieving review status')
 
   auth.add_auth_options(parser)
+  _add_codereview_select_options(parser)
   options, args = parser.parse_args(args)
+  _process_codereview_select_options(parser, options)
   if args:
     parser.error('Unsupported args: %s' % args)
   auth_config = auth.extract_auth_config_from_options(options)
 
+  if options.issue is not None:
+    if not options.field or not options.forced_codereview:
+      parser.error('--issue may only be specified in conjunction with --field'
+                   ' and either --rietveld or --gerrit')
+
   if options.field:
-    cl = Changelist(auth_config=auth_config)
+    cl = Changelist(auth_config=auth_config, issue=options.issue,
+                    codereview=options.forced_codereview)
     if options.field.startswith('desc'):
       print(cl.GetDescription())
     elif options.field == 'id':
       issueid = cl.GetIssue()
       if issueid:
         print(issueid)
     elif options.field == 'patch':
       patchset = cl.GetPatchset()
       if patchset:
         print(patchset)
@@ skipping 1806 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   setup_color.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)