The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b6d006bf5eb32c19eccac5fd0272a098572b55fb

commit b6d006bf5eb32c19eccac5fd0272a098572b55fb
Author: David Bokan <bokan@chromium.org>
Date: Thu May 10 15:52:54 2018

[BlinkGenPropertyTrees] Add more scrolling tests expectations

Most "scrolling" tests in Blink are in the fast/scrolling and
fast/events directories, the latter due to testing touch, wheel,
keyboard, etc. events. Many of these will use eventSender and so avoid
the composited path entirely so they provide just some mildly useful
main-thread scrolling coverage. Some do use gpuBenchmarking and are thus
more useful.

Bug:  836913 , 840017 , 841342 , 841423 
Change-Id: Idc4c2fae7ee7a48f074df8b3df5a027a75c82f71
Reviewed-on: https://chromium-review.googlesource.com/1052823
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557533}
[modify] https://crrev.com/b6d006bf5eb32c19eccac5fd0272a098572b55fb/third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-gen-property-trees
[modify] https://crrev.com/b6d006bf5eb32c19eccac5fd0272a098572b55fb/third_party/WebKit/LayoutTests/TestExpectations
[modify] https://crrev.com/b6d006bf5eb32c19eccac5fd0272a098572b55fb/third_party/WebKit/LayoutTests/VirtualTestSuites
[add] https://crrev.com/b6d006bf5eb32c19eccac5fd0272a098572b55fb/third_party/WebKit/LayoutTests/virtual/threaded/fast/scrolling/README.txt

Closing this out since it's similar to the blocking bug