[webkit-changes] [WebKit/WebKit] 28c7ac: REGRESSION (254304 at main): Sidebar on MDN articles ...

[Simon Fraser]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 28c7acb04ba03729dcec6381d959d1857f025b88
      https://github.com/WebKit/WebKit/commit/28c7acb04ba03729dcec6381d959d1857f025b88
  Author: Simon Fraser <simon.fraser at apple.com>
  Date:   2022-09-14 (Wed, 14 Sep 2022)

  Changed paths:
    A LayoutTests/compositing/tiling/sticky-change-to-tiled-expected.html
    A LayoutTests/compositing/tiling/sticky-change-to-tiled.html
    A LayoutTests/compositing/tiling/sticky-with-backdrop-expected.html
    A LayoutTests/compositing/tiling/sticky-with-backdrop.html
    M Source/WebCore/rendering/RenderLayerCompositor.cpp

  Log Message:
  -----------
  REGRESSION (254304 at main): Sidebar on MDN articles is often misplaced
https://bugs.webkit.org/show_bug.cgi?id=245192
<rdar://99848107>

Reviewed by Alan Bujtas and Tim Nguyen.

For "viewport constrained" scrolling elements, we need to pass the viewportAnchorLayer()
to the scrolling tree. This happened in the main code path, but this path that
runs when toggling to/from tiled layers, or with backdrops, also needs updating.

* LayoutTests/compositing/tiling/sticky-change-to-tiled-expected.html: Added.
* LayoutTests/compositing/tiling/sticky-change-to-tiled.html: Added.
* LayoutTests/compositing/tiling/sticky-with-backdrop-expected.html: Added.
* LayoutTests/compositing/tiling/sticky-with-backdrop.html: Added.
* Source/WebCore/rendering/RenderLayerCompositor.cpp:
(WebCore::RenderLayerCompositor::didChangePlatformLayerForLayer):

Canonical link: https://commits.webkit.org/254496@main