Implement git cl upload -b BUG --bug=BUG.

tests/git_cl_test.py

Index: tests/git_cl_test.py
diff --git a/tests/git_cl_test.py b/tests/git_cl_test.py
index cc01ae3b829da5dbb5a2862a7a10aee44ade7886..a1d58a875172c92044de4fd0ab42f7e77150a956 100755
--- a/tests/git_cl_test.py
+++ b/tests/git_cl_test.py
@@ -208,6 +208,13 @@ class TestGitClBasic(unittest.TestCase):
          123, 4, 'chrome-review.source.com')
     test('https://chrome-review.source.com/bad/123/4', fail=True)
 
+  def test_get_bug_line_value(self):
+    self.assertEqual(git_cl._get_bug_line_value('', ''), '')
+    self.assertEqual(git_cl._get_bug_line_value('', '123,v8:456'), '123,v8:456')
+    self.assertEqual(git_cl._get_bug_line_value('v8', '456'), 'v8:456')
+    self.assertEqual(git_cl._get_bug_line_value('v8', 'chromium:123,456'),
+                     'chromium:123,v8:456')
+
 
 class TestGitCl(TestCase):
   def setUp(self):
@@ -688,6 +695,14 @@ class TestGitCl(TestCase):
       self.assertEqual(
           'Must specify reviewers to send email.\n', stderr.getvalue())
 
+  def test_bug_on_cmd(self):
+    self._run_reviewer_test(
+        ['--bug=500658,proj:123'],
+        'desc\n\nBUG=500658,proj:123',
+        '# Blah blah comment.\ndesc\n\nBUG=500658,proj:1234',
+        'desc\n\nBUG=500658,proj:1234',
+        [])
+
   def test_dcommit(self):
     self.mock(git_cl.sys, 'stdout', StringIO.StringIO())
     self.calls = (