GitLab

- accept_const_keyword

And invalid jscomp_error value:
- checkStructDictInheritance

Both are obsolete in new versions of closure compiler
(which I'm trying to update to).

TBR=tbreisacher@chromium.org,stuartmorgan@chromium.org
BUG=none
TEST=closure compilation works

Review URL: https://codereview.chromium.org/1316563002

Cr-Commit-Position: refs/heads/master@{#345260}