[webkit-changes] [WebKit/WebKit] 2ef700: Arrow key keyboard scrolling in Safari doesn't work

[Richard Robinson]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 2ef7008f5d540228d290e4b46b8f703ddfaf4245
      https://github.com/WebKit/WebKit/commit/2ef7008f5d540228d290e4b46b8f703ddfaf4245
  Author: Richard Robinson <richard_robinson2 at apple.com>
  Date:   2023-06-06 (Tue, 06 Jun 2023)

  Changed paths:
    M Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm

  Log Message:
  -----------
  Arrow key keyboard scrolling in Safari doesn't work
https://bugs.webkit.org/show_bug.cgi?id=257754
rdar://110333066

Reviewed by Aditya Keerthi.

264230 at main added an early return in `RemoteScrollingTreeMac::didCommitTree` to ensure that
`RemoteScrollingTreeMac::startPendingScrollAnimations` wasn't called in the case that there
are zero pending scrolling animations. However, this only checked for non-keyboard scroll
animations. This resulted in the early return happening even when there are pending keyboard
scroll animations causing the keyboard scrolling animations to never start.

This PR fixes this by early returning only if there are zero non-keyboard scroll animations
and zero keyboard scroll animations.

Note that there are existing tests for this which did also catch this, but EWS doesn't run
with the necessary configuration.

* Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm:
(WebKit::RemoteScrollingTreeMac::didCommitTree):

Canonical link: https://commits.webkit.org/264913@main