The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9c6fb254a2122d0de0b5b8debed525538caa7e02

commit 9c6fb254a2122d0de0b5b8debed525538caa7e02
Author: Alexander Timin <altimin@chromium.org>
Date: Fri Mar 09 21:08:39 2018

[scheduler] Add TaskDurationPerTaskType.{Foreground,Background} histograms.

Add new histograms to capture per-task-type task duration for different
renderer visibility states separately.

BUG= 820494 
R=rkaplow@chromium.org
CC=panicker@chromium.org

Change-Id: Icce8e262cc87a4d3f73809abdbcda34a124a1bb9
Reviewed-on: https://chromium-review.googlesource.com/955855
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542222}
[modify] https://crrev.com/9c6fb254a2122d0de0b5b8debed525538caa7e02/third_party/WebKit/Source/platform/scheduler/renderer/renderer_metrics_helper.cc
[modify] https://crrev.com/9c6fb254a2122d0de0b5b8debed525538caa7e02/third_party/WebKit/Source/platform/scheduler/renderer/renderer_metrics_helper.h
[modify] https://crrev.com/9c6fb254a2122d0de0b5b8debed525538caa7e02/tools/metrics/histograms/histograms.xml