Remove invalid compiler arg:

Remove invalid compiler arg:
- 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

Committed: https://crrev.com/bc7915c52045d2507440a8eccbe050368bc5e641
Cr-Commit-Position: refs/heads/master@{#345260}

[Dan Beam, 2015-08-25 03:19:59]

dbeam@chromium.org changed reviewers:
+ stuartmorgan@chromium.org

[Dan Beam, 2015-08-25 03:20:28]

The CQ bit was checked by dbeam@chromium.org

[commit-bot: I haz the power, 2015-08-25 03:20:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1316563002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1316563002/1

[commit-bot: I haz the power, 2015-08-25 05:03:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-25 05:03:48]

Patchset 1 (id:??) landed as
https://crrev.com/bc7915c52045d2507440a8eccbe050368bc5e641
Cr-Commit-Position: refs/heads/master@{#345260}

[stuartmorgan, 2015-09-02 22:18:39]

ios/ LGTM