Drive-by refactoring of some unsafe code in stylo
Some stuff I found while thinking about other things between stylo and layout.
Third commit requires Gecko changes because I removed `From<u32>` for `FontLanguageOverride` and replaced it by the unsafe `FontLanguageOverride::from_u32` method.
Fix ServiceWorker in multiprocess
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FIX#15217FIX#26100
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There is no need to set the dirty descendants flag unsafely from the layout side
for elements with pending restyles, we can do that on the DOM side when draining
the restyles from the Document.
Check the BHM option before starting it in multi-process mode.
In multi-process mode, if the BHM option is set start with one otherwise don't.
I didn't add a test for this. However if I should I'd be happy to be pointed to where similar tests are done (meaning tests of options yielding the expected state) because I didn't find my way in all those tests.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#26088
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- [x] These changes do not require tests because they are minor enough to not require one.
Avoid infinitely looping CSS transitions.
This change addresses the long-standing issue of CSS transitions not ending appropriately. It does not fundamentally change the way we process transitions/animations.
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- [x] These changes fix#20379
- [x] There are tests for these changes
More layout cleanups from the introduction of a lifetime in LayoutDom<T>
What can I say, the follow-up fixes just kept coming to my door one by one, I couldn't just tell them to go away.
For clarity, I introduce <LayoutDom<Element>>::parent_node_ref to contain
the remaining unsafety bits out of composed_parent_node_ref which is more
complex than just a field access.
webgl: Don't dirty canvas element while in immersive mode.
There are various WebGL APIs that are supposed to trigger a frame composite at the end of the event loop when they're used. We enforce this via dirtying the canvas element and ensuring that reflow occurs for normal content. This is redundant when we're using immersive mode and incurs extra work by the layout thread and compositor that inhibits the immersive rendering performance.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix (part of) #26019
- [x] These changes do not require tests because we do not have infrastructure to test immersive mode on CI.
Reduce unnecessary layout queries in babylon.js content
Every frame, Babylon.js compares the width property of the webgl canvas element to its clientWidth. This incurs two layout operations every frame - one to get the dimensions of the element, and at the end of the frame to construct a display list and send that to webrender.
These changes introduce the concept of cached layout values which are constructed from the result of layout queries. These cached values are automatically invalidated when a new layout operation takes place, but as long as only the query operations that stored a cached value are used and the DOM is not otherwise dirtied, the cached values will remain valid and no further layout operations will take place.
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix (part of) #26019
- [x] These changes do not require tests because we have no infrastructure to test whether or not reflow occurred.
