[webkit-changes] [WebKit/WebKit] 4cd43d: Some compositing configurations cause duplicated I...

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  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 4cd43d6a32eaf36096893b3260ed15ff208bddc5
      https://github.com/WebKit/WebKit/commit/4cd43d6a32eaf36096893b3260ed15ff208bddc5
  Author: Etienne Segonzac <sgz at apple.com>
  Date:   2023-05-26 (Fri, 26 May 2023)

  Changed paths:
    A LayoutTests/interaction-region/position-only-update-expected.txt
    A LayoutTests/interaction-region/position-only-update.html
    M Source/WebCore/rendering/EventRegion.cpp
    M Source/WebCore/rendering/EventRegion.h
    M Source/WebCore/rendering/RenderLayerBacking.cpp
    M Source/WebCore/rendering/RenderLayerBacking.h

  Log Message:
  -----------
  Some compositing configurations cause duplicated InteractionRegion layers with an offset
https://bugs.webkit.org/show_bug.cgi?id=257317
<rdar://109589854>

Reviewed by Tim Horton and Simon Fraser.

When a compositing layer becomes a simple container, clear any existing
interaction region. Otherwise we might keep duplicates around since the
layer won't repaint.

* Source/WebCore/rendering/EventRegion.h:
* Source/WebCore/rendering/EventRegion.cpp:
(WebCore::EventRegion::clearInteractionRegions):
* Source/WebCore/rendering/RenderLayerBacking.h:
* Source/WebCore/rendering/RenderLayerBacking.cpp:
(WebCore::RenderLayerBacking::clearInteractionRegions):
New method to clear InteractionRegions from an EventRegion.
(WebCore::RenderLayerBacking::updateDrawsContent):
Clear the interaction regions if the layer has no painted content.

* LayoutTests/interaction-region/position-only-update-expected.txt: Added.
* LayoutTests/interaction-region/position-only-update.html: Added.
New test capturing the *very specific* configuration causing the issue.

Canonical link: https://commits.webkit.org/264622@main