Add lots of Arc’s in style, and prepare for using DOMRefCell
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`DOMRefCell` usage is not there year because of thread-safety questions, but I have this much already that I’d like to land before it bitrots.
r? @emilio
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a script query.
This will, rather unfortunately, mean that we might repaint two times if we've
deferred a paint, then get an out-of-band reflow. Still seemed better than not
suppressing paints at all.
Fixes#13131
Fix ridiculous DOM proxy getter performance
This implements the missing shadowing checks that were causing us to take many slow paths when dealing with proxy objects. Verified by running `tests/html/binding_perf.html` before and after and observing a 12x improvement.
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Use new name convention for Servo binding functions.
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This is the Servo part of [bug 1296173](https://bugzilla.mozilla.org/show_bug.cgi?id=1296173).
r? @bholley
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Support multiple backgrounds in both servo and stylo
(Commits do not build individually, but split up for review)
These patches make all of the background- properties accept multiple values, and add the layout code to display them.
Still needs some cleanup, and some testing, but it seems to work.
r? @SimonSapin
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Make GeckoDeclarationBlock refcounted
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This makes GeckoDeclarationBlock refcounted, so that it can share most of the logic Gecko currently uses for its existing `css::Declaration`. Although this is almost only useful for Gecko side, doing this in Servo side eliminates additional object allocation for holding it in the Gecko side.
Its Gecko side code change is in [bug 1296186](https://bugzilla.mozilla.org/show_bug.cgi?id=1296186). We may not want to land this before that part also gets reviewed.
r? @Manishearth
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