Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: b6306634c70b5891fdec1b19f14f0b297453204d
https://github.com/WebKit/WebKit/commit/b6306634c70b5891fdec1b19f14f0b297453204d
Author: Wenson Hsieh <wenson_hs...@apple.com>
Date: 2023-03-23 (Thu, 23 Mar 2023)
Changed paths:
M Source/WebCore/page/scrolling/ScrollingCoordinatorTypes.cpp
M Source/WebCore/page/scrolling/ScrollingCoordinatorTypes.h
M Source/WebCore/page/scrolling/ScrollingStateScrollingNode.cpp
M Source/WebCore/page/scrolling/ScrollingStateScrollingNode.h
M
Source/WebKit/Shared/RemoteLayerTree/RemoteScrollingCoordinatorTransaction.cpp
M Source/WebKit/Shared/WebCoreArgumentCoders.serialization.in
M Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm
Log Message:
-----------
[UI-side compositing] Two
imported/w3c/web-platform-tests/css/cssom-view/scroll-behavior tests fail
https://bugs.webkit.org/show_bug.cgi?id=254335
rdar://106116027
Reviewed by Tim Horton and Simon Fraser.
When UI-side compositing is enabled, the following two WPT fail:
•
imported/w3c/web-platform-tests/css/cssom-view/scroll-behavior-main-frame-root.html
•
imported/w3c/web-platform-tests/css/cssom-view/scroll-behavior-main-frame-window.html
Both of these tests wait for an animated scroll to a specific scroll position
`(x, y)` to finish
before resetting the scroll position to `(0, 0)` and immediately starting
another animated scroll to
the same `(x, y)` destination. When UI-side compositing is enabled and
scrolling tree updates are
propagated to the UI process in batches via remote layer tree commits, this
means that the animated
scroll to `(x, y)` replaces the `m_requestedScrollData` set by the instant
programmatic scroll to
`(0, 0)`.
However, because the UI process already thinks that the scroll position of the
scrolling node is at
`(x, y)` due to the previous animated scroll (right before the page tries to
instantly scroll to
`(0, 0)`), the next layer tree commit that contains the requested animated
scroll to `(x, y)`
results in a no-op.
To address this, we add a new member to `RequestedScrollData` that carries
information about the
previously requested scrolling update, which is only populated in the case
where an animated scroll
immediately follows a non-animated scroll. We then use this data to perform an
immediate scroll in
the UI process right before starting the animated scroll, such that the
animated scroll begins from
the correct position.
* Source/WebCore/page/scrolling/ScrollingCoordinatorTypes.cpp:
(WebCore::RequestedScrollData::merge):
Add a helper method to coalesce data from an incoming requested scroll into
existing requested
scroll data. See changes in `ScrollingStateScrollingNode` for more details.
* Source/WebCore/page/scrolling/ScrollingCoordinatorTypes.h:
(WebCore::RequestedScrollData::operator== const):
* Source/WebCore/page/scrolling/ScrollingStateScrollingNode.cpp:
(WebCore::ScrollingStateScrollingNode::setRequestedScrollData):
In the case where the scrolling tree state already holds a requested scrolling
update, use the
helper method above to merge the incoming requested scroll data into the
existing one. Typically,
this simply results in the incoming request replacing the existing one;
however, in the case where
we have an incoming animated scrolling request that immediately follows a
non-animated scrolling
request, we'll additionally set `requestedDataBeforeAnimatedScroll`.
* Source/WebCore/page/scrolling/ScrollingStateScrollingNode.h:
*
Source/WebKit/Shared/RemoteLayerTree/RemoteScrollingCoordinatorTransaction.cpp:
* Source/WebKit/Shared/WebCoreArgumentCoders.serialization.in:
* Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm:
(WebKit::RemoteScrollingTreeMac::startPendingScrollAnimations):
If `requestedDataBeforeAnimatedScroll` exists, then use
`ScrollingTreeScrollingNode::scrollTo` to
set the scroll position right before embarking on the animated scroll.
Canonical link: https://commits.webkit.org/262041@main
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