[scheduling_metrics] Create //components/scheduling_metrics

Create a component to unify renderer process and browser process
metrics, including EQT.

R=jochen@chromium.org
CC=alexclarke@chromium.org,eseckler@chromium.org,skyostil@chromium.org,gab@chromium.org,fdoray@chromium.org,npm@chromium.org,tdresser@chromium.org

Change-Id: I8a356206f6beeebba7de0c0d597a1cc60607dd8b
Reviewed-on: https://chromium-review.googlesource.com/1135133
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578276}
25 files changed