Add dschinazi as networking reviewer for histograms.xml

This will allow members of the networking team to
make minor changes to their networking histograms.

R=rkaplow@chromium.org

Change-Id: Ic9d0879745f84dfe2463adc33b392bc1d3191071
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2207933
Commit-Queue: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Auto-Submit: David Schinazi <dschinazi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770568}

tools/metrics/histograms/OWNERS

@@ -14,6 +14,7 @@ per-file histograms.xml=alexilin@chromium.org
 per-file histograms.xml=altimin@chromium.org # Scheduling-related metrics.
 per-file histograms.xml=csharrison@chromium.org
 per-file histograms.xml=cthomp@chromium.org  # For security-related metrics only.
+per-file histograms.xml=dschinazi@chromium.org  # For networking-related metrics only.
 per-file histograms.xml=schenney@chromium.org
 per-file histograms.xml=tbansal@chromium.org
 per-file histograms.xml=tby@chromium.org # For chrome knowledge team metrics only.