1840025 - Use ScrollMode::Smooth in nsSliderFrame::PageScroll

Status: RESOLVED FIXED

(Core :: Panning and Zooming, task, P3)

Description

[Botond Ballo [:botond]]

In bug 1331390, we used ScrollMode::SmoothMsd on this line even though the other codepath in that function uses ScrollMode::Smooth, to work around bug 1835600.

Now that bug 1835600 is fixed we should revert to using ScrollMode::Smooth. I originally tried to do this in https://phabricator.services.mozilla.com/D181420, but found that it regresses helper_scrollbartrack_click_overshoot.html on Mac only. There are indications that this is an issue with the test (details in bug 1835600 comment 7).

This bug tracks fixing the test issue and landing the change.

Comment 1

[Botond Ballo [:botond]]

Relevant logs from an earlier Try push:

window.scrollMaxY = 19150
after first scrollend, window.scrollY = 834
after second scrollend, window.scrollY = 16003

Maybe three scrollends does the trick on Mac :)

Comment 2

[Botond Ballo [:botond]]

The use of ScrollMode::SmoothMsd has caused a user-noticeable regression, bug 1851021.

While the failure of helper_scrollbartrack_click_overshoot.html with ScrollMode::Smooth on Mac remains to be investigated and fixed, since that failure seems to be a test issue, I'm inclined to say that fixing the regression is more important than preserving the test coverage from this test on one platform.

Therefore, I'll make the change while disabling the test for now, and file a follow-up for re-enabling the test.

Comment 3

[Botond Ballo [:botond]]

Attachment: Bug 1840025 - Use ScrollMode::Smooth in nsSliderFrame::PageScroll. r=rzvncj

This restores the scrolling physics used in PageScroll to what it was
before bug 1331390.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b904d35c98f7
Use ScrollMode::Smooth in nsSliderFrame::PageScroll. r=rzvncj

Comment 5

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/b904d35c98f7