repohooks: Allow BUG=chromium:1234.

We previously just allowed references to the chromium-os and
chrome-os-partner trackers.

Something else will need to be changed to linkify the BUG
line in the web interface.

BUG=none
TEST=referenced an arbitrary chromium issue when first uploading this change

Change-Id: Ibb85016eb8263cdf62a3e579eb2d62bc50e917ac
Reviewed-on: https://gerrit.chromium.org/gerrit/13941
Reviewed-by: David McMahon <djmm@chromium.org>
Tested-by: David McMahon <djmm@chromium.org>
Tested-by: Daniel Erat <derat@chromium.org>
Commit-Ready: Daniel Erat <derat@chromium.org>
diff --git a/pre-upload.py b/pre-upload.py
index f730563..db3199f 100755
--- a/pre-upload.py
+++ b/pre-upload.py
@@ -283,12 +283,13 @@
 
 def _check_change_has_bug_field(project, commit):
   """Check for a correctly formatted 'BUG=' field in the commit message."""
-  BUG_RE = r'\nBUG=([Nn]one|(chrome-os-partner|chromium-os):\d+)'
+  BUG_RE = r'\nBUG=([Nn]one|(chrome-os-partner|chromium|chromium-os):\d+)'
 
   if not re.search(BUG_RE, _get_commit_desc(commit)):
     msg = ('Changelist description needs BUG field (after first line):\n'
-           'BUG=chromium-os:99999 (for public tracker)\n'
+           'BUG=chromium-os:9999 (for public tracker)\n'
            'BUG=chrome-os-partner:9999 (for partner tracker)\n'
+           'BUG=chromium:9999 (for browser tracker)\n'
            'BUG=None')
     return HookFailure(msg)