tree 35010c5078e97686e8798934697c46b08d2e3dba
parent 919aeb989a73073e2f1d75e53d7d882b3cc61ca8
author zalan@apple.com <zalan@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1655954523 +0000
committer zalan@apple.com <zalan@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> 1655954523 +0000

RenderElement::addLayers should check for dialog content before inserting layers
https://bugs.webkit.org/show_bug.cgi?id=241874

Reviewed by Simon Fraser.

addLayers stops (recursive) descending in the render tree soon after it finds a root (R) with layer.
It says that if a subtree root (R) has a layer then all layers in this subtree must have already been inserted into the layer tree at an earlier time.
(it simply assumes that any layer in the subtree is a child of (R), or some other layers in the subtree)

<div id=container>
  <div id=R>
    <div id=child>

The insertion is bottom to top; we attach
1, (child) to (R) first
2, followed by (R) to (container)
addLayers assumes that when (R) is being inserted (#2), we don't have to descend into (R)'s subtree since any renderer's layer that was inserted before (at #1) must have already been parented.

However toplayer/backdrop content is an exception where the parent layer may be outside of the subtree but still accessible. In such cases subsequent insertions (and the recursive nature of finding layer parents) could lead to double parenting where we try to insert the same layer into the layer tree multiple times.

* Source/WebCore/rendering/RenderElement.cpp:
(WebCore::addLayers):
(WebCore::RenderElement::insertedIntoTree):
(WebCore::RenderElement::addLayers): Deleted.
* Source/WebCore/rendering/RenderElement.h:

Canonical link: https://commits.webkit.org/251772@main


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@295767 268f45cc-cd09-0410-ab3c-d52691b4dbfc