[css-grid] Enable masonry feature flag

[stwrt]

8046191

[css-grid] Enable masonry feature flag
https://bugs.webkit.org/show_bug.cgi?id=247074
rdar://101595681

Reviewed by Tim Nguyen and Brent Fulgham.

Enable masonry by default on platforms.

* Source/WTF/Scripts/Preferences/UnifiedWebPreferences.yaml:

Canonical link: https://commits.webkit.org/274661@main

32311df

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	❌ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
✅ 🛠 🧪 merge	✅ 🛠 watch		🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash ebef83e)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
🛠 🧪 jsc	✅ 🧪 api-ios	🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
	✅ 🛠 watch		❌ 🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[brentfulgham]

Looks good, suggest enabling WKL, too.

[webkit-early-warning-system]

EWS run on current version of this PR (hash 32311df)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	❌ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim		✅ 🛠 jsc-armv7
✅ 🛠 🧪 merge	✅ 🛠 watch		🧪 jsc-armv7-tests
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 274661@main (8046191): https://commits.webkit.org/274661@main

Reviewed commits have been landed. Closing PR #24414 and removing active labels.

[Loirooriol]

But it doesn't seem stable enough? Like I don't think the CSSWG resolved on whether masonry should be built on top of grid or be an independent layout. w3c/csswg-drafts#9041 wants to discuss alternative paths forward. w3c/csswg-drafts#9733 may even rename "masonry" to something else.

So I don't understand enabling it by default.

[nt1m]

Please don't read too much into feature flag states :)

[brentfulgham]

There are a variety of reasons why we sometimes activate a feature in our unreleased code base that are not because we are about to ship the feature. When we plan to ship in production builds to Apple platforms we will indicate that in our release notes. Until then, monitoring our source repository is a very bad way to guess what we will actually ship.

If it makes you feel better, we could conditionalize this on Cocoa ports to avoid impacting other platforms.

[Loirooriol]

Yes, even if you don't ship it in Safari, I don't think this should be enabled by default in WebKitGTK or such.

[brentfulgham]

@Loirooriol Please see #24972