Ah, this test is marked as fail but is actually passing flakily. This test needs to be rewritten.

sahel, can you take a look? The test expectations file says that this test is supposed to only pass with TouchpadAndWheelScrollLatching.

wheel-scroll-latching-on-scrollbar.html is also very flaky (though, marked as such) and probably needs to be rewritten too:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_tests&tests=wheel-scroll-latching-on-scrollbar.html

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/44da1d7297d2602dc2f5775caf900a873da05b91

commit 44da1d7297d2602dc2f5775caf900a873da05b91
Author: Sahel Sharify <sahel@chromium.org>
Date: Mon Jul 31 20:32:46 2017

mouse-wheel-scroll-latching.html test rewritten

By changing the test to use promises, assertion checks happen after giving the
scroll enough time to get processed.

TEST=fast/events/wheel/mouse-wheel-scroll-latching.html,
virtual/wheelscrolllatching/fast/events/wheel/mouse-wheel-scroll-latching.html

Bug:  735130 
Change-Id: I1c13bf7eb4be88be942cea40e0bd3228ea2830d9
Reviewed-on: https://chromium-review.googlesource.com/591771
Commit-Queue: Sahel Sharifymoghaddam <sahel@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490793}
[modify] https://crrev.com/44da1d7297d2602dc2f5775caf900a873da05b91/third_party/WebKit/LayoutTests/TestExpectations
[delete] https://crrev.com/0c8943d7614bec3e70874e4d8744087d0f5b20af/third_party/WebKit/LayoutTests/fast/events/wheel/mouse-wheel-scroll-latching-expected.txt
[modify] https://crrev.com/44da1d7297d2602dc2f5775caf900a873da05b91/third_party/WebKit/LayoutTests/fast/events/wheel/mouse-wheel-scroll-latching.html