Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 7d4f344fa9a70f3b92972faeaf1352c03d384b74
https://github.com/WebKit/WebKit/commit/7d4f344fa9a70f3b92972faeaf1352c03d384b74
Author: Alan Baradlay <[email protected]>
Date: 2023-09-19 (Tue, 19 Sep 2023)
Changed paths:
A LayoutTests/fast/dynamic/display-none-iframe-async-layout-expected.html
A LayoutTests/fast/dynamic/display-none-iframe-async-layout.html
M Source/WebCore/dom/Document.cpp
Log Message:
-----------
Office.com is slow to respond
https://bugs.webkit.org/show_bug.cgi?id=261741
<rdar://112494003>
Reviewed by Antti Koivisto.
1. we do _not_ construct renderers for “display: none” iframes
2. we do construct render tree for the “display: none” iframe’s content
we do #2 because JS may ask for geometry information on content inside a
“display: none” iframe.
e.g.
<div><iframe srcdoc=“text” style="display: none;" id=iframe></iframe></div>
where:
iframe.contentDocument.body.offsetHeight should return the value of “18px”
the markup above triggers the following 2 render trees:
Main document:
RenderView
HTML RenderBlock
BODY RenderBody
DIV RenderBlock
(^^ no renderer here for the “display: none” iframe)
iframe document:
RenderView
HTML RenderBlock
BODY RenderBody
#text RenderText
(^^ this is the content _inside_ the "display: none" iframe)
We not only construct a render tree for the invisible iframe content, but also
(as part of the tree construction) we schedule an async layout on them
This patch drops such async layout requests on the floor and keep the renderers
dirty until after either
1. sync layout is triggered (JS -> DOM API)
2. iframe becomes visible (display != none)
* LayoutTests/fast/dynamic/display-none-iframe-async-layout-expected.html:
Added.
* LayoutTests/fast/dynamic/display-none-iframe-async-layout.html: Added.
* Source/WebCore/dom/Document.cpp:
(WebCore::Document::shouldScheduleLayout const):
Canonical link: https://commits.webkit.org/268148@main
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