Remove unused DomainBoundCerts.* histograms

R=mattm@chromium.org

Bug: 755431
Change-Id: I5f2a66c4bd66186f30a5a44d27132232b5a1d1d3
Reviewed-on: https://chromium-review.googlesource.com/877409
Commit-Queue: Nick Harper <nharper@chromium.org>
Reviewed-by: Matt Mueller <mattm@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530989}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: faa2517606be8ddd20b15449b0644699728f8a66
4 files changed