Bug 305628 – Regression(305673@main): Crash under RefCountDebugger::applyRefDerefThreadingCheck()

• Status: RESOLVED
• Resolution: FIXED
• Component: Accessibility

[Chris Dumez]

305673@main introduced a thread safety issue:
```
Thread 8 Crashed::  Dispatch queue: com.apple.root.user-initiated-qos.cooperative
0   JavaScriptCore                	       0x10df43d88 WTFCrash + 0
1   WebCore                       	       0x324a1e068 WTF::RefCountDebugger::applyRefDerefThreadingCheck(unsigned int, WTF::RefCountIsThreadSafe) const + 232
2   WebCore                       	       0x324a1dea0 WTF::RefCountDebugger::willRef(unsigned int, WTF::RefCountIsThreadSafe) const + 52
3   WebCore                       	       0x324b21e28 WTF::RefCountedBase::ref() const + 48
4   WebCore                       	       0x325269544 WTF::RefCountedAndCanMakeWeakPtr<WebCore::PlatformSpeechSynthesizer>::ref() const + 32
5   WebCore                       	       0x325269478 WTF::DefaultRefDerefTraits<WebCore::PlatformSpeechSynthesizer>::ref(WebCore::PlatformSpeechSynthesizer&) + 32
6   WebCore                       	       0x325269c30 WTF::Ref<WebCore::PlatformSpeechSynthesizer, WTF::RawPtrTraits<WebCore::PlatformSpeechSynthesizer>, WTF::DefaultRefDerefTraits<WebCore::PlatformSpeechSynthesizer>>::Ref(WebCore::PlatformSpeechSynthesizer&) + 40
7   WebCore                       	       0x325265728 WTF::Ref<WebCore::PlatformSpeechSynthesizer, WTF::RawPtrTraits<WebCore::PlatformSpeechSynthesizer>, WTF::DefaultRefDerefTraits<WebCore::PlatformSpeechSynthesizer>>::Ref(WebCore::PlatformSpeechSynthesizer&) + 40
8   WebCore                       	       0x325267d98 invocation function for block in WebCore::PlatformSpeechSynthesizer::initializeVoiceList() + 64
```

[Radar WebKit Bug Importer]

<rdar://problem/168285130>

[Chris Dumez]

Pull request: https://github.com/WebKit/WebKit/pull/56694

[EWS]

Committed 305701@main (477da9e88b08): <https://commits.webkit.org/305701@main>

Reviewed commits have been landed. Closing PR #56694 and removing active labels.