GetChangeDescriptionFromGitiles followup: future todo for no gitiles.

R=andybons@chromium.org
BUG=603207, 605563

Review URL: https://codereview.chromium.org/1913913002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@300194 0039d316-1c4b-4281-b951-d872f2087c98

gerrit_util.py

@@ -491,6 +491,10 @@ def GetChangeDescriptionFromGitiles(url, revision):
   """
   parsed = urlparse.urlparse(url)
   path = '%s/+/%s?format=json' % (parsed.path, revision)
+  # Note: Gerrit instances that Chrome infrastructure uses thus far have all
+  # enabled Gitiles, which allowes us to execute this call. This isn't true for
+  # all Gerrit instances out there. Thus, if line below fails, consider adding a
+  # fallback onto actually fetching ref from remote using pure git.
   return ReadHttpJsonResponse(CreateHttpConn(parsed.netloc, path))['message']