[webkit-changes] [WebKit/WebKit] f719f8: ASSERTION FAILED: scrollerImp == scroller->scrolle...

[Nikos Mouchtaris]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: f719f87b07476ed574a5a450bf39931218d52798
      https://github.com/WebKit/WebKit/commit/f719f87b07476ed574a5a450bf39931218d52798
  Author: Nikolaos Mouchtaris <nmouchtaris at apple.com>
  Date:   2023-05-01 (Mon, 01 May 2023)

  Changed paths:
    M Source/WebCore/page/scrolling/mac/ScrollerMac.h
    M Source/WebCore/page/scrolling/mac/ScrollerMac.mm
    M Source/WebCore/page/scrolling/mac/ScrollerPairMac.mm
    M Source/WebCore/page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.mm

  Log Message:
  -----------
  ASSERTION FAILED: scrollerImp == scroller->scrollerImp() if closing a window while scrolling
https://bugs.webkit.org/show_bug.cgi?id=255886
rdar://108469342

Reviewed by Simon Fraser.

The order of destruction is ScrollingTreeScrollingNodeDelegateMac -> ScrollerPairMac ->
ScrollerMac. We don't want to release the scroller imps in ScrollingTreeScrollingNodeDelegateMac
because we have yet to remove the delegate from the scroller imps. This can lead to a state where
we get a call to convertContentPoint when our reference to the scroller imps in ScrollerMac are
already released. To resolve this, move this call to ~ScrollerPairMac and move the ScrollerMac
calls to the individual scroller imps to their own function and call them in ~ScrollerPairMac.

* Source/WebCore/page/scrolling/mac/ScrollerPairMac.mm:
(-[WebScrollerImpPairDelegateMac scrollerImpPair:convertContentPoint:toScrollerImp:]):
(WebCore::ScrollerPairMac::~ScrollerPairMac):
* Source/WebCore/page/scrolling/mac/ScrollingTreeScrollingNodeDelegateMac.mm:
(WebCore::ScrollingTreeScrollingNodeDelegateMac::~ScrollingTreeScrollingNodeDelegateMac):

Canonical link: https://commits.webkit.org/263557@main