[webkit-changes] [WebKit/WebKit] f56f38: REGRESSION (263108 at main): [ Ventura debug ] ASSERT...

[Wenson Hsieh]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: f56f38532d22a8b13af72d165f9f97eaa2975b83
      https://github.com/WebKit/WebKit/commit/f56f38532d22a8b13af72d165f9f97eaa2975b83
  Author: Wenson Hsieh <wenson_hsieh at apple.com>
  Date:   2023-04-21 (Fri, 21 Apr 2023)

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

  Log Message:
  -----------
  REGRESSION (263108 at main): [ Ventura debug ] ASSERTION FAILED: WTF::WeakPtr<WebKit::RemoteScrollingCoordinatorProxy, WTF::DefaultWeakPtrImpl>::operator->() const
https://bugs.webkit.org/show_bug.cgi?id=255788
rdar://108369779

Reviewed by Tim Horton.

Add a missing bounce to the main thread before calling `scrollingTreeNodeDidBeginScrollSnapping` or
`scrollingTreeNodeDidEndScrollSnapping` in the UI process on macOS.

* Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.h:
* Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm:
(WebKit::RemoteScrollingTreeMac::scrollingTreeNodeWillStartScroll):
(WebKit::RemoteScrollingTreeMac::scrollingTreeNodeDidEndScroll):

Also harden some existing logic (as well as the new methods below) so that they explicitly protect
`this` when calling out to the main thread.

(WebKit::RemoteScrollingTreeMac::scrollingTreeNodeDidBeginScrollSnapping):
(WebKit::RemoteScrollingTreeMac::scrollingTreeNodeDidEndScrollSnapping):

Canonical link: https://commits.webkit.org/263271@main