Presubmit: Treat changes with Gerrit-style Tbr: header as TBRed.

Bug: 735158
Change-Id: I1444f34c84862f542909d0b70c5cdfd02394526c
Reviewed-on: https://chromium-review.googlesource.com/541638
Reviewed-by: Aaron Gable <agable@chromium.org>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>

presubmit_support.py

@@ -568,7 +568,7 @@ class InputApi(object):
   @property
   def tbr(self):
     """Returns if a change is TBR'ed."""
-    return 'TBR' in self.change.tags
+    return 'TBR' in self.change.tags or self.change.TBRsFromDescription()
 
   def RunTests(self, tests_mix, parallel=True):
     tests = []