Support --enable-auto-submit in `git cl split`

With default True.

This CL was uploaded by git cl split.

R=jochen@chromium.org
Bug: 927178
Change-Id: Ie0a68ed7ca381e1bb33341badca153bf409bb376
Reviewed-on: https://chromium-review.googlesource.com/c/1470402
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
diff --git a/git_cl.py b/git_cl.py
index 97f4372..72a9b92 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -4604,6 +4604,11 @@
                          "infrastructure. Try to upload these not during high "
                          "load times (usually 11-3 Mountain View time). Email "
                          "infra-dev@chromium.org with any questions.")
+  parser.add_option('-a', '--enable-auto-submit', action='store_true',
+                    default=True,
+                    help='Sends your change to the CQ after an approval. Only '
+                         'works on repos that have the Auto-Submit label '
+                         'enabled')
   options, _ = parser.parse_args(args)
 
   if not options.description_file:
@@ -4614,7 +4619,7 @@
 
   return split_cl.SplitCl(options.description_file, options.comment_file,
                           Changelist, WrappedCMDupload, options.dry_run,
-                          options.cq_dry_run)
+                          options.cq_dry_run, options.enable_auto_submit)
 
 
 @subcommand.usage('DEPRECATED')