All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=821101

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=a6a3cfaf86230ac1c1e5af2eedee53db1b1eb51b96ae89abf6692ac8ab6e0e8e


Bot(s) for this bug's original alert(s):

android-nexus7v2

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14ec4636440000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/14ec4636440000

Android: WindowAndroid returns mouse wheel scroll factor by jinsukkim@chromium.org
https://chromium.googlesource.com/chromium/src/+/00e4698b772d9c266b88b69ea7f0824afe194f2e

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

 Issue 821102  has been merged into this issue.

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14cd949e440000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/14cd949e440000

Fix scrolling perf regression by jinsukkim@chromium.org
https://chromium-review.googlesource.com/c/chromium/src/+/961503/1

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14b757ce440000

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/14b757ce440000

Fix scrolling perf regression by jinsukkim@chromium.org
https://chromium-review.googlesource.com/c/chromium/src/+/961503/3

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4583ba5da2ed63d2565da9b91feac50a574647ab

commit 4583ba5da2ed63d2565da9b91feac50a574647ab
Author: Jinsuk Kim <jinsukkim@chromium.org>
Date: Wed Mar 14 04:58:56 2018

Fix scrolling perf regression

pixels per mouse_scroll_wheel_tick was being set wrong (should have
been wheel_scroll_factor but was the value divided by dip_scale
was set), hence decreased the scroll rate and caused the regression.
This CL fixes the issue. Now WindowAndroid stores wheel_scroll_factor
(instead of tick multiplier) which is accessed much more often, for
efficiency's sake.

Bug:  821101 
Change-Id: I99e81fdfc21ec101a99092c50555be4f429d7a20
Reviewed-on: https://chromium-review.googlesource.com/961503
Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543013}
[modify] https://crrev.com/4583ba5da2ed63d2565da9b91feac50a574647ab/content/browser/renderer_host/render_widget_host_view_android.cc
[modify] https://crrev.com/4583ba5da2ed63d2565da9b91feac50a574647ab/ui/android/event_forwarder.cc
[modify] https://crrev.com/4583ba5da2ed63d2565da9b91feac50a574647ab/ui/android/window_android.cc
[modify] https://crrev.com/4583ba5da2ed63d2565da9b91feac50a574647ab/ui/android/window_android.h