Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: a7cd2f5b0eb407ec31e9815dc5c9c3491e5f4451
https://github.com/WebKit/WebKit/commit/a7cd2f5b0eb407ec31e9815dc5c9c3491e5f4451
Author: Ben Nham <[email protected]>
Date: 2026-09-04 (Fri, 04 Sep 2026)
Changed paths:
A
LayoutTests/http/tests/site-isolation/intersection-observer/resources/report-intersections-frame.html
A
LayoutTests/http/tests/site-isolation/intersection-observer/resources/same-site-middle-frame.html
A
LayoutTests/http/tests/site-isolation/intersection-observer/target-in-cross-site-frame-nested-in-same-site-frame-expected.txt
A
LayoutTests/http/tests/site-isolation/intersection-observer/target-in-cross-site-frame-nested-in-same-site-frame.html
A
LayoutTests/http/tests/site-isolation/only-broadcast-frame-geometry-from-frames-with-cross-process-descendants-expected.txt
A
LayoutTests/http/tests/site-isolation/only-broadcast-frame-geometry-from-frames-with-cross-process-descendants.html
M Source/WebCore/page/FrameTree.cpp
M Source/WebCore/page/FrameTree.h
M Source/WebCore/page/Page.cpp
M Source/WebCore/page/RemoteFrameView.cpp
Log Message:
-----------
[Site Isolation] Only broadcast frame geometry from frames with a
cross-process descendant
https://bugs.webkit.org/show_bug.cgi?id=322890
rdar://problem/186140629
Reviewed by Kiet Ho and Matt Woodrow.
On every rendering update, each local frame broadcasts its frame geometry to
every other process
rendering the page.
This is mostly unnecessary, because remote frames only care about geometry from
ancestors, not the
entire tree:
- IntersectionObserver: computeClippedRectInRootContentsSpace uses clip
geometry from ancestors
only, e.g. layoutViewportRect and visibleRectOfChild.
- LocalFrameView::windowClipRect: root frames in the remote process calculate
their clip rect from
their parent's visibleRectInParent.
- exposedContentRect: frames in the remote process calculate their
exposedContentRect from their
parent's exposedContentRectInParent.
To fix this, skip calculating geometry for any child that is entirely local to
this process.
Additionally, if a local frame has no remote descendants, then we should send
nothing, since no
remote frame exists that could use that geometry.
One complication here is with remote frames nested under multiple local frames:
Local main frame => local child frame => remote grandchild frame
When we process the local main frame in the syncLocalFrameInfoToRemote loop, we
still have to send
geometry associated with that local main frame even though its direct child is
local. This is
because an IntersectionObserver in the remote grandchild frame walks all the
way up to the root of
the frame tree and uses clipping rectangles from all ancestor nodes.
We add a layout test to test this specific frame hierarchy with
IntersectionObserver. Note that it
is similar to but differs from the existing nested-cross-origin-iframe.sub.html
IntersectionObserver
test in WPT, since the frame hierarchy in that test contains only remote child
frames.
There is an obvious follow-up optimization here to stop broadcasting frame
geometry and only send
it to remote processes that actually need that particular state. That requires
more significant
refactoring so we'll optimize that in a subsequent patch.
Tests:
http/tests/site-isolation/intersection-observer/target-in-cross-site-frame-nested-in-same-site-frame.html
http/tests/site-isolation/only-broadcast-frame-geometry-from-frames-with-cross-process-descendants.html
*
LayoutTests/http/tests/site-isolation/intersection-observer/resources/report-intersections-frame.html:
Added.
*
LayoutTests/http/tests/site-isolation/intersection-observer/resources/same-site-middle-frame.html:
Added.
*
LayoutTests/http/tests/site-isolation/intersection-observer/target-in-cross-site-frame-nested-in-same-site-frame-expected.txt:
Added.
*
LayoutTests/http/tests/site-isolation/intersection-observer/target-in-cross-site-frame-nested-in-same-site-frame.html:
Added.
*
LayoutTests/http/tests/site-isolation/only-broadcast-frame-geometry-from-frames-with-cross-process-descendants-expected.txt:
Added.
*
LayoutTests/http/tests/site-isolation/only-broadcast-frame-geometry-from-frames-with-cross-process-descendants.html:
Added.
* Source/WebCore/page/Page.cpp:
(WebCore::Page::syncLocalFrameInfoToRemote):
* Source/WebCore/page/FrameTree.cpp:
(WebCore::FrameTree::containsLocalFrame const):
* Source/WebCore/page/FrameTree.h:
* Source/WebCore/page/RemoteFrameView.cpp:
(WebCore::RemoteFrameView::childFrameOwnerToRootContentTransform const):
(WebCore::RemoteFrameView::absoluteToChildFrameOwnerLocalTransform const):
Canonical link: https://commits.webkit.org/320553@main
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