Inconclusive so far; before the revert we were failing 9 builds out of 10, afterwards the bot failed 1 out of 4.  That looks better at a glance, but not better enough I'm willing to say conclusively this CL was the cause.

Failed again.  OK, I don't think my revert helped.  Relanding.

Marking untriaged.

I am working on flaky Autoscroll tests on Mac.

virtual/user-activation-v2/fast/events/middleClickAutoscroll-in-iframe.html looks also flaky. Let me mark that as flaky too.

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=fast%2Fevents%2FmiddleClickAutoscroll

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8ab077adf16071d84347f63f137537d35f97526f

commit 8ab077adf16071d84347f63f137537d35f97526f
Author: Makoto Shimazu <shimazu@chromium.org>
Date: Tue Aug 14 06:21:46 2018

Mark middleClickAutoscroll-in-iframe.html in user-activation-v2 as flaky

TBR=sahel@chromium.org
NOTRY=true

Bug:  873435 
Change-Id: I1c063da5ac84b6c50c61fdc24cd976e9059dc4f4
Reviewed-on: https://chromium-review.googlesource.com/1174074
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582848}
[modify] https://crrev.com/8ab077adf16071d84347f63f137537d35f97526f/third_party/WebKit/LayoutTests/TestExpectations

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1bbf9f17d20c1851986bfae19eabf16755c05afc

commit 1bbf9f17d20c1851986bfae19eabf16755c05afc
Author: Xida Chen <xidachen@chromium.org>
Date: Wed Aug 15 12:42:46 2018

Mark fast/events/middleClickAutoscroll-in-iframe.html timeout on Mac

TBR=wjmaclean@chromium.org
NOTRY=true

Bug:  873435 
Change-Id: I2c68d19a86abddf00a3420850fd03a59acb26647
Reviewed-on: https://chromium-review.googlesource.com/1175695
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583223}
[modify] https://crrev.com/1bbf9f17d20c1851986bfae19eabf16755c05afc/third_party/WebKit/LayoutTests/TestExpectations

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3af420d0f4d2c370a477186db5b90e0fe7db9b11

commit 3af420d0f4d2c370a477186db5b90e0fe7db9b11
Author: David Bokan <bokan@chromium.org>
Date: Fri Aug 24 16:41:35 2018

Fix pinch zoom tests on Mac

These tests:
virtual/threaded/fast/events/pinch/pinch-zoom-into-center.html
virtual/threaded/fast/events/pinch/pinch-zoom-pan-position-fixed.html
pinch-zoom-pan-within-zoomed-viewport.html

were breaking because Mac doesn't support touch events and the pinch
was being done using touch. I've changed to use a touchpad source as
this doesn't affect the meaning of the tests as well as some minor
cleanups.

While here, I also rewrote a number of tests to use gesture-util.js and
the async/await style which is more readable and easier to produce
non-flaky tests.

TBR=nasko@chromium.org

Bug:  854199 , 873435 , 877494 , 877361 
Change-Id: I19f6e199fea694013d3dceaeb32c881059301f1d
Reviewed-on: https://chromium-review.googlesource.com/1185238
Commit-Queue: David Bokan <bokan@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Sahel Sharify <sahel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585871}
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/TestExpectations
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/fast/scroll-behavior/overscroll-behavior.html
[delete] https://crrev.com/2150cdb8fe59c54e803aec058c661b9e0b953e4d/third_party/WebKit/LayoutTests/virtual/threaded/animations/invisible-composited-animations-prevent-scroll-expected.html
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/virtual/threaded/animations/invisible-composited-animations-prevent-scroll.html
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/virtual/threaded/fast/events/pinch/gesture-pinch-zoom-scroll-bubble.html
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/virtual/threaded/fast/events/pinch/pinch-zoom-pan-position-fixed.html
[modify] https://crrev.com/3af420d0f4d2c370a477186db5b90e0fe7db9b11/third_party/WebKit/LayoutTests/virtual/threaded/fast/events/pinch/pinch-zoom-pan-within-zoomed-viewport.html

Patch above should have improved virtual/threaded/fast/events/pinch/gesture-pinch-zoom-scroll-bubble.html - Will check back in a few days at https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=virtual%2Fthreaded%2Ffast%2Fevents%2Fpinch%2Fgesture-pinch-zoom-scroll-bubble.html

The NextAction date has arrived: 2018-08-29

virtual/threaded/fast/events/pinch/gesture-pinch-zoom-scroll-bubble.html has been all green since #11.

middleClickAutoscroll test flake are related to crbug.com/874162, virtual/threaded/fast/scroll-behavior/smooth-scroll/mousewheel-scroll.html is the only remaining test here.

I am closing this bug since virtual/threaded/fast/scroll-behavior/smooth-scroll/mousewheel-scroll.html is taken care of in crbug.ocm/865755