Deflake virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-ancho…

Deflake virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html

This test seemed to be flaky because it didn't have the correct initial scroll
position. This change makes it identical to ongoing-smooth-scroll-anchors by
scrolling to the edge of the anchor before beginning the test which has
made it pass 100% on my local testing 100 tries, compared to timing out about
10% of the time before.

BUG=670066
TEST=virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html

Review-Url: https://codereview.chromium.org/2535753008
Cr-Commit-Position: refs/heads/master@{#456496}
Committed: https://chromium.googlesource.com/chromium/src/+/ed1e5e77e4b90ca252684531f14c1e6fb97e0ea7

[flackr, 2016-12-01 16:07:41]

flackr@chromium.org changed reviewers:
+ ymalik@chromium.org

[flackr, 2016-12-01 16:07:42]

PTAL, thanks. I discovered the flakiness was actually due to an incorrect
initial assumption. The scroll position seems to start at the top-left of the
page, not the anchor element as the test expects. Setting the initial scroll
position seems to have fixed all of the flakiness locally.

https://codereview.chromium.org/2535753008/diff/1/third_party/WebKit/LayoutTe...
File third_party/WebKit/LayoutTests/TestExpectations (right):

https://codereview.chromium.org/2535753008/diff/1/third_party/WebKit/LayoutTe...
third_party/WebKit/LayoutTests/TestExpectations:975: crbug.com/665577 [ Linux
Win ]
virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html
[ Pass Failure ]
I wasn't sure if I should remove the expected failure, but I guess that can be
left up to the bug which it is filed against https://crbug.com/665577. This
removes the Timeout expectation that was added in https://crbug.com/670066 due
to flakiness.

[ymalik, 2016-12-01 17:39:43]

lgtm, thanks!

[flackr, 2016-12-01 17:41:12]

The CQ bit was checked by flackr@chromium.org

[commit-bot: I haz the power, 2016-12-01 17:41:35]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[skobes, 2016-12-01 18:40:19]

skobes@chromium.org changed reviewers:
+ skobes@chromium.org

[skobes, 2016-12-01 18:40:19]

Does this indicate a problem in the resetting of scroll position between test
runs?  Why would the initial scroll position be flaky?

[commit-bot: I haz the power, 2016-12-01 19:16:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-01 19:16:44]

Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[flackr, 2017-03-09 21:55:31]

On 2016/12/01 18:40:19, skobes wrote:
> Does this indicate a problem in the resetting of scroll position between test
> runs?  Why would the initial scroll position be flaky?

No, the problem was that with an initial width of 0px, if we changed the size of
the #changer before the scroll position changed by a full pixel then you would
snap before the changer, whereas if the scroll had moved past it then it would
snap correctly. The non right-to-left test uses a non zero initial size for the
changer (presumably to avoid this potential race) already.

[flackr, 2017-03-09 21:56:48]

The CQ bit was checked by flackr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-09 21:57:17]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[skobes, 2017-03-09 22:26:06]

lgtm

[commit-bot: I haz the power, 2017-03-09 23:28:19]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-09 23:28:19]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[flackr, 2017-03-13 20:25:45]

The CQ bit was checked by flackr@chromium.org

[flackr, 2017-03-13 20:25:46]

The patchset sent to the CQ was uploaded after l-g-t-m from ymalik@chromium.org,
skobes@chromium.org
Link to the patchset: https://codereview.chromium.org/2535753008/#ps40001
(title: "Scroll after verifying initial position.")

[commit-bot: I haz the power, 2017-03-13 20:26:11]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-13 21:36:03]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1489436745991430,
"parent_rev": "80da37a9ae40452f920fdb8a5bbd55454f7e560c", "commit_rev":
"ed1e5e77e4b90ca252684531f14c1e6fb97e0ea7"}

[commit-bot: I haz the power, 2017-03-13 21:36:47]

Description was changed from

==========
Deflake
virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html

This test seemed to be flaky because it didn't have the correct initial scroll
position. This change makes it identical to ongoing-smooth-scroll-anchors by
scrolling to the edge of the anchor before beginning the test which has
made it pass 100% on my local testing 100 tries, compared to timing out about
10% of the time before.

BUG=670066
TEST=virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html
==========

to

==========
Deflake
virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html

This test seemed to be flaky because it didn't have the correct initial scroll
position. This change makes it identical to ongoing-smooth-scroll-anchors by
scrolling to the edge of the anchor before beginning the test which has
made it pass 100% on my local testing 100 tries, compared to timing out about
10% of the time before.

BUG=670066
TEST=virtual/threaded/fast/scroll-behavior/smooth-scroll/ongoing-smooth-scroll-vertical-rl-anchors.html

Review-Url: https://codereview.chromium.org/2535753008
Cr-Commit-Position: refs/heads/master@{#456496}
Committed:
https://chromium.googlesource.com/chromium/src/+/ed1e5e77e4b90ca252684531f14c...
==========

[commit-bot: I haz the power, 2017-03-13 21:36:48]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/ed1e5e77e4b90ca252684531f14c...