http://crrev.com/2730703002 has context on what needs to happen to get the warnings to show up in CQ (not just in buildbots). Once we have CQ coverage, we can remove workarounds with more confidence.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/022e76c4e2597f27c442eaecacaabdc708480ff2

commit 022e76c4e2597f27c442eaecacaabdc708480ff2
Author: pwnall <pwnall@chromium.org>
Date: Thu Mar 30 23:42:00 2017

Document the fact that leveldb sign warnings aren't getting fixed.

BUG= 698013 

Review-Url: https://codereview.chromium.org/2788663003
Cr-Commit-Position: refs/heads/master@{#460932}

[modify] https://crrev.com/022e76c4e2597f27c442eaecacaabdc708480ff2/third_party/leveldatabase/BUILD.gn