GitLab

[sb] Transfer histogram ownership to Varun.

Varun owns rolling out a new storage layer for safe browsing, which is
currently taking over in stable.  So these should all be removed
soonish.

BUG=705809,701209

Review-Url: https://codereview.chromium.org/2787563002
Cr-Commit-Position: refs/heads/master@{#460647}