[webkit-changes] [WebKit/WebKit] b6fc29: Composited mix-blend-mode inside backdrop-filter d...

[mattwoodrow]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: b6fc29dd94bdc86d254249e952947f1ca287dd11
      https://github.com/WebKit/WebKit/commit/b6fc29dd94bdc86d254249e952947f1ca287dd11
  Author: Matt Woodrow <mattwoodrow at apple.com>
  Date:   2023-09-26 (Tue, 26 Sep 2023)

  Changed paths:
    A LayoutTests/css3/filters/backdrop/backdrop-filter-with-composited-blend-mode-expected.html
    A LayoutTests/css3/filters/backdrop/backdrop-filter-with-composited-blend-mode.html
    M Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp

  Log Message:
  -----------
  Composited mix-blend-mode inside backdrop-filter doesn't use the backdrop-filter as its composited group.
https://bugs.webkit.org/show_bug.cgi?id=149553
<rdar://22854172>

Reviewed by Simon Fraser.

Backdrop-filter creates a stacking context (and isolated group for blend modes), so we should add child layers
onto the primary layer, not as siblings of the backdrop layer.

* LayoutTests/css3/filters/backdrop/backdrop-filter-with-composited-blend-mode-expected.html: Added.
* LayoutTests/css3/filters/backdrop/backdrop-filter-with-composited-blend-mode.html: Added.
* Source/WebCore/platform/graphics/ca/GraphicsLayerCA.cpp:
(WebCore::GraphicsLayerCA::updateSublayerList):

Canonical link: https://commits.webkit.org/268477@main