Move files from components/metrics/proto to third_party/metrics_proto

This reflects that the source of truth for these files is considered to
be the server side versions of these protos, and that changes to them
should originate outside of chromium code.

Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: If78332a355d9fd0deac821763877613e1e6bdc69
Reviewed-on: https://chromium-review.googlesource.com/575767
Commit-Queue: Steven Holte <holte@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#510642}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: f9d5ed670c20f297af669cf548e4f9618c2312e4
5 files changed