GitLab

From leak reports, it seems like sometimes the pending operations queue
just keeps growing and growing, but we still don't know why... so
DumpWithoutCrashing (once per backend lifetime) if it seems ridiculously
long.

Thanks to mef@ for the idea.

Bug: 809199
Change-Id: Ia949be30e50ddcd6f800c4c26268966b6e298bc0
Reviewed-on: https://chromium-review.googlesource.com/1210367
Commit-Queue: Maks Orlovich <morlovich@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589236}