Add histogram to track RTL domain navigations

Change-Id: I1d76ec4fdc41d21552ec4109223be94537484ec0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1613970
Reviewed-by: Tommy Li <tommycli@chromium.org>
Reviewed-by: Emily Stark <estark@chromium.org>
Commit-Queue: Christopher Thompson <cthomp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661856}
5 files changed