Remove obsolete FineTiming histograms

R=avi@chromium.org

Bug: 984212
Change-Id: I89b90f7a40d864cf0e0962916a8cb712195a34f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1703331
Auto-Submit: Joe Mason <joenotcharles@google.com>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Nik Bhagat <nikunjb@chromium.org>
Commit-Queue: Joe Mason <joenotcharles@google.com>
Cr-Commit-Position: refs/heads/master@{#678902}