GitLab

The mash/mustash project was shut down over a year ago. Clean up some
obsolete comments and DEPS.

Bug: none
Change-Id: I9d9ce137a4cf42330eb104be7c9613a4c4ab0675
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2210631Reviewed-by: Michael Wasserman <msw@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770842}