The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/41eb3228ed142eaec3b006613441f665a91b0ec9

commit 41eb3228ed142eaec3b006613441f665a91b0ec9
Author: Yao Xiao <yaoxia@chromium.org>
Date: Mon Sep 10 15:29:08 2018

Add UMA for WindowOpen.FromAdSubrame/Script

Indicating whether the page called window.open() from an ad
subframe and/or with an ad script in the stack.

Bug: 880923
Change-Id: Ia64fea4f32bc62c3ee5aceb3731a236b88b1c807
Reviewed-on: https://chromium-review.googlesource.com/1206676
Commit-Queue: Yao Xiao <yaoxia@chromium.org>
Reviewed-by: Nate Chapin <japhet@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589921}
[modify] https://crrev.com/41eb3228ed142eaec3b006613441f665a91b0ec9/chrome/browser/subresource_filter/ad_tagging_browsertest.cc
[modify] https://crrev.com/41eb3228ed142eaec3b006613441f665a91b0ec9/third_party/blink/renderer/core/page/create_window.cc
[modify] https://crrev.com/41eb3228ed142eaec3b006613441f665a91b0ec9/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/41eb3228ed142eaec3b006613441f665a91b0ec9/tools/metrics/histograms/histograms.xml