The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/398545566409ddc8a8ffa67b48bcb6e65282f4ec

commit 398545566409ddc8a8ffa67b48bcb6e65282f4ec
Author: Xida Chen <xidachen@chromium.org>
Date: Wed Sep 27 17:10:33 2017

Disable ScrollbarAppearanceTest.HugeScrollingThumbPosition on Android

TBR=bokan@chromium.org
NOTRY=true

Bug:  769350 
Change-Id: I6bc4cb6c15e89c6450e06b0bee1949f9f50ba5f1
Reviewed-on: https://chromium-review.googlesource.com/687794
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504712}
[modify] https://crrev.com/398545566409ddc8a8ffa67b48bcb6e65282f4ec/third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ab01f1a8c03a610ff32b4fa53fec556a67aba487

commit ab01f1a8c03a610ff32b4fa53fec556a67aba487
Author: Xida Chen <xidachen@chromium.org>
Date: Wed Sep 27 17:50:22 2017

Properly disable ScrollbarAppearanceTest.HugeScrollingThumbPosition on Android

TBR=bokan@chromium.org
NOTRY=true

Bug:  769350 
Change-Id: I11bae8d5ff0fb18938d220531560fdfa2aa9b39e
Reviewed-on: https://chromium-review.googlesource.com/688034
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504723}
[modify] https://crrev.com/ab01f1a8c03a610ff32b4fa53fec556a67aba487/third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

Thanks, I'll take a look

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a049172ecdd300aae44218d81ab762d29ae949c3

commit a049172ecdd300aae44218d81ab762d29ae949c3
Author: David Bokan <bokan@chromium.org>
Date: Mon Oct 02 16:01:40 2017

Add ASSERTs to HugeScrollingThumbPosition test

This test was turned off due to being flaky. From the logs, it seems
that the thumb position is sometimes off by 6px. I suspect the mock
theme isn't getting applied in time or that we're keeping around a
horizontal scrollbar from a previous test for too long.

I've added some ASSERTs here and reenabled the test to hopefully narrow
in on the cause. I've also added a BeginFrame() after scrolling. That
might also remove the flake. The ASSERTs should be removed once the
cause is determined (or the BeginFrame() fixes it).

Bug:  769350 
Change-Id: Id1fb0e5865c86c68b27b33b272171ba3a6ee7d53
Reviewed-on: https://chromium-review.googlesource.com/693148
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505630}
[modify] https://crrev.com/a049172ecdd300aae44218d81ab762d29ae949c3/third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/50af2a9f4c7d7e5a9e04c2e003bbb39a04832a2e

commit 50af2a9f4c7d7e5a9e04c2e003bbb39a04832a2e
Author: David Bokan <bokan@chromium.org>
Date: Wed Oct 04 13:46:05 2017

More diagnostic ASSERTS for flaky scrollbar test

I added ASSERTs to this test in r505630 but none of them tripped and the
test is still flaky. I've replaced the ASSERTS with a new set.

Bug:  769350 
Change-Id: Ib4f3819de8e01e346fb1e882fe17b1811e0a30bb
Reviewed-on: https://chromium-review.googlesource.com/698266
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506378}
[modify] https://crrev.com/50af2a9f4c7d7e5a9e04c2e003bbb39a04832a2e/third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de787538f5df9e7edfd32d92a8795eccbd87a144

commit de787538f5df9e7edfd32d92a8795eccbd87a144
Author: David Bokan <bokan@chromium.org>
Date: Fri Oct 06 15:31:36 2017

Fix flaky test HugeScrollingThumbPosition

Looks like the cause is that the scrollbar margin, which we mock in a
custom WebThemeEngine gets read once when the ScrollbarThemeOverlay is
created and is then cached. However, ScrollbarThemes are static so once
it's created once we never recreate it. Thus, if another test runs
before this one that doesn't use our mocked WebThemeEngine, this test
will use the real margins.

Longer term this will be fixed by making ScrollbarThemes not be global
singletons (being worked on in the context of  crbug.com/740879 ), then we
can just recreate a ScrollbarTheme in this test. For now, we'll just
account for the used margin in our expectation to prevent flakiness.

Bug:  769350 
Change-Id: I8e93ac3def151963d8e07cf0bb9cc203f8d51279
Reviewed-on: https://chromium-review.googlesource.com/703491
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#507078}
[modify] https://crrev.com/de787538f5df9e7edfd32d92a8795eccbd87a144/third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

Bot's been green for a while now so this looks fixed.