Bring metrics protos in sync with google3

Bug: 851163
Change-Id: I6a6aa135f9e1cab496ad6b7fe007bdc8e1ac94f0
Reviewed-on: https://chromium-review.googlesource.com/1178632
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Felipe Salazar <felipesalazar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583876}
7 files changed