GitLab

For privacy, metrics from inner frames are recorded with the top frame's
origin. Given that WebOTP is supported in cross-origin iframes, it's
better to indicate such information in the |Outcome| metrics to
understand the impact and implications. e.g. does user decline more
often if the API is used in an cross-origin iframe.

UKM collection review:
https://docs.google.com/document/d/12-cSbZ2_ztM4u2USo7cVBlZ5rIiQefkdGxz-XdQfa7Q/edit#

Bug: 1136506, 1127397
Change-Id: I08d9f720ab8b3832bb47d1fb3575ef7093d8fc57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2576588Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835189}