[GStreamer][WebRTC][Rice] Improve backend safety on NetworkProcess side

[philn]

dfdc4d4

[GStreamer][WebRTC][Rice] Improve backend safety on NetworkProcess side
https://bugs.webkit.org/show_bug.cgi?id=305699

Reviewed by Xabier Rodriguez-Calvar.

Store the RiceBackend as a ThreadSafeWeakPtr and access it from Rice callbacks and GSources as a
RefPtr.

* Source/WebKit/NetworkProcess/webrtc/rice/RiceBackend.cpp:
(WebKit::RiceBackend::gatherSocketAddresses):

Canonical link: https://commits.webkit.org/305812@main

0469f76

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	⏳ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	❌ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
	✅ 🧪 api-ios		✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash a7a755d)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
	✅ 🧪 api-ios		✅ 🛠 gtk
	✅ 🛠 vision	🧪 mac-wk2	❌ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 0469f76)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	⏳ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	❌ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 api-mac-debug	✅ 🛠 wpe-cairo-libwebrtc
	✅ 🧪 api-ios		✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-wk2-stress	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🧪 mac-intel-wk2
	✅ 🛠 tv-sim	✅ 🛠 mac-safer-cpp
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 305812@main (dfdc4d4): https://commits.webkit.org/305812@main

Reviewed commits have been landed. Closing PR #56766 and removing active labels.