Make --send-mail more useful by not requiring -r

Previously, --send-mail required -r to pass. Now it uses the R=|TBR= lines from
the description, which is much more useful.

R=dpranke@chromium.org
BUG=
TEST=


Review URL: http://codereview.chromium.org/8735018

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@112221 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/git_cl.py b/git_cl.py
index aff809e..c0d9c94 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -920,10 +920,6 @@
   upload_args.extend(['--server', cl.GetRietveldServer()])
   if options.emulate_svn_auto_props:
     upload_args.append('--emulate_svn_auto_props')
-  if options.send_mail:
-    if not options.reviewers:
-      DieWithError("Must specify reviewers to send email.")
-    upload_args.append('--send_mail')
   if options.from_logs and not options.message:
     print 'Must set message for subject line if using desc_from_logs'
     return 1
@@ -951,6 +947,10 @@
     upload_args.extend(['--description', change_desc.description])
     if change_desc.reviewers:
       upload_args.extend(['--reviewers', change_desc.reviewers])
+    if options.send_mail:
+      if not change_desc.reviewers:
+        DieWithError("Must specify reviewers to send email.")
+      upload_args.append('--send_mail')
     cc = ','.join(filter(None, (cl.GetCCList(), options.cc)))
     if cc:
       upload_args.extend(['--cc', cc])