Also virtual/prefer_compositing_to_lcd_text/scrollbars/custom-scrollbar-adjust-on-inactive-pseudo.html: https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=custom-scrollbar

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/603dfcf4b383529aa3f403feabe2d003249e70a2

commit 603dfcf4b383529aa3f403feabe2d003249e70a2
Author: Mike West <mkwst@chromium.org>
Date: Wed Nov 29 16:34:04 2017

Skip 'custom-scrollbar-inactive-pseudo.html' layout tests.

Very flaky.

TBR=ojan@chromium.org

Bug: 789567
Change-Id: Ie457f0b626d3fe12af6f21b07fed9852c5902f13
Reviewed-on: https://chromium-review.googlesource.com/796890
Commit-Queue: Mike West <mkwst@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520137}
[modify] https://crrev.com/603dfcf4b383529aa3f403feabe2d003249e70a2/third_party/WebKit/LayoutTests/TestExpectations

Hm... this doesn't really look flaky to me anymore?

This seems pretty flaky, not just on mac: https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_tests&tests=virtual%2Frootlayerscrolls%2Fscrollbars%2Fcustom-scrollbar-inactive-pseudo.html

chaopeng@ can you investigate?

I am not able to reproduce the failure locally. I tried this command:

python third_party/WebKit/Tools/Scripts/run-webkit-tests -t Default -f "virtual/prefer_compositing_to_lcd_text/scrollbars/custom-scrollbar-"

Is there any other flag I can try?

I also checked the log (https://storage.googleapis.com/chromium-layout-test-archives/Mac10_12_Tests/7804/layout-test-results/results.html), the tests are failed on inactive state not apply to the scrollbar, maybe the page.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d1e47ed6c79dffbecb84ab8ec8128714d8daae2b

commit d1e47ed6c79dffbecb84ab8ec8128714d8daae2b
Author: John Abd-El-Malek <jam@chromium.org>
Date: Fri Dec 01 15:17:02 2017

Update layout test expectations for some flaky tests.

virtual/rootlayerscrolls/scrollbars/custom-scrollbar-inactive-pseudo.html
virtual/prefer_compositing_to_lcd_text/scrollbars/custom-scrollbar-inactive-pseudo.html
virtual/prefer_compositing_to_lcd_text/scrollbars/custom-scrollbar-adjust-on-inactive-pseudo.html
are flaky on Linux as well

virtual/gpu-rasterization/images/image-hover-display-alt.html is flaky

TBR=avi@chromium.org
NOTRY=true

Bug: 789567, 789478,  790025 
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I6f52e55a3a3a4573750d971f1ce7247448579061
Reviewed-on: https://chromium-review.googlesource.com/801256
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520942}
[modify] https://crrev.com/d1e47ed6c79dffbecb84ab8ec8128714d8daae2b/third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService
[modify] https://crrev.com/d1e47ed6c79dffbecb84ab8ec8128714d8daae2b/third_party/WebKit/LayoutTests/TestExpectations

It seems the tests is not flaky anymore. https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=custom-scrollbar-inactive-pseudo.html

Agree the non-virtual version looks good on the dashboard - you can remove that from the Expectations.

The prefer_compositing virtual test suite still has the occasional failure - particularly on Linux dbg and Mac.

An additional flag to try against flakiness would be --iterations=100 or --repeat-each=100 --no-retry-failures.