The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/80c6537f623a4a5ba60cd9fbc33bd93f5843d536

commit 80c6537f623a4a5ba60cd9fbc33bd93f5843d536
Author: Eric Robinson <ericrobinson@chromium.org>
Date: Mon Jun 18 21:03:11 2018

Adding metrics for safe browsing activation on redirects.

Add a metric to indicate where in the redirect chain the safe browsing
activation occurred, either at the start, middle, or end, or in the
case where the navigation is direct, in the only position.

Bug: 851545
Change-Id: I39d0848aee825db287171a2c63862bdb434373a1
Reviewed-on: https://chromium-review.googlesource.com/1099647
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Commit-Queue: Eric Robinson <ericrobinson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568162}
[modify] https://crrev.com/80c6537f623a4a5ba60cd9fbc33bd93f5843d536/components/subresource_filter/content/browser/subresource_filter_safe_browsing_activation_throttle.cc
[modify] https://crrev.com/80c6537f623a4a5ba60cd9fbc33bd93f5843d536/components/subresource_filter/content/browser/subresource_filter_safe_browsing_activation_throttle.h
[modify] https://crrev.com/80c6537f623a4a5ba60cd9fbc33bd93f5843d536/components/subresource_filter/content/browser/subresource_filter_safe_browsing_activation_throttle_unittest.cc
[modify] https://crrev.com/80c6537f623a4a5ba60cd9fbc33bd93f5843d536/tools/metrics/histograms/enums.xml
[modify] https://crrev.com/80c6537f623a4a5ba60cd9fbc33bd93f5843d536/tools/metrics/histograms/histograms.xml