According to Gerrit totals: shaves 510.7 KiB.

If you find specific images broken by this CL (in theory this shouldn't
happen, but...), I'd suggest reverting the specific image rather than
the entire set.  Many of these images are compressed safely (and
slightly).  Something that is more likely to break: animation.

R=agrieve@chromium.org
BUG=not running this script more often

Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Idc1683fbd4a7402c700c946d75973c4804419623
Reviewed-on: https://chromium-review.googlesource.com/901961
Commit-Queue: Dan Beam (no longer on Chrome) <dbeam@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Jamie Walch <jamiewalch@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534934}