The InteractionRegion layers' order should match the paint order

[etiennesegonzac]

c370b1b

The InteractionRegion layers' order should match the paint order
https://bugs.webkit.org/show_bug.cgi?id=253678
<rdar://105700167>

Reviewed by Tim Horton.

Propagate the Interaction Regions creation's order (which matches the
paint order) all the way to the RemoteLayerTree.
The content process is now in charge of ordering/deduping the regions.
And we don't do per-element region uniting anymore.

* Source/WebCore/rendering/EventRegion.h:
Remove the InteractionRegionByElement HashMap.
Add HashSets to dedupe regions by bounds.
* Source/WebCore/rendering/EventRegion.cpp:
(WebCore::EventRegionContext::uniteInteractionRegions):
(WebCore::EventRegionContext::copyInteractionRegionsToEventRegion):
Use a vector to accumulate interaction regions in order.
Prevent duplicated bounds.
(WebCore::EventRegion::dump const):
Remove the test-only ordering code so existing tests cover the actual order.

* Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeInteractionRegionLayers.mm:
(WebKit::insertInteractionRegionLayersForLayer):
Break when the first non-InteractionRegion-layer is encountered.
(They always come first.)
(WebKit::updateLayersForInteractionRegions):
Update the sublayers while maintaining the order we get from the event
region. Reuse existing layers when the bounds match.

* LayoutTests/interaction-region/overlap-expected.txt: Added.
* LayoutTests/interaction-region/overlap.html: Added.
Add a test covering the content-side deduplication.
* LayoutTests/interaction-region/split-inline-link-expected.txt:
* LayoutTests/interaction-region/wrapped-inline-link-expected.txt:
Update test after the per-element uniting removal.

Canonical link: https://commits.webkit.org/261578@main

d62cfd6

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	✅ 🛠 tv	✅ 🧪 mac-wk2	🧪 api-gtk
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash d62cfd6)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-wk2	🧪 api-gtk
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 261578@main (c370b1b): https://commits.webkit.org/261578@main

Reviewed commits have been landed. Closing PR #11332 and removing active labels.