GitLab

This CL introduces new UMA histograms that record types of commits and
updates processed by the sync engine. For each datatype there is a
separate histogram so that the data can indicate bugs or regression in
individual data types.

Bug: 859859
Change-Id: Iaeaa7a657ebe7d9d6fbbd329152162c5acaadc01
Reviewed-on: https://chromium-review.googlesource.com/1131507
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577592}