<rdar://problem/113915816>

Pull request: https://github.com/WebKit/WebKit/pull/16710

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 JavaScriptCore 0x139beb070 WTFCrash + 24 (Assertions.cpp:327) 1 WebCore 0x282c197ac WTFCrashWithInfo(int, char const*, char const*, int) + 36 (Assertions.h:768) 2 WebCore 0x2830eba28 WebCore::JSEventListener::ensureJSFunction(WebCore::ScriptExecutionContext&) const + 664 (JSEventListener.h:163) 3 WebCore 0x2830eaeec WebCore::JSEventListener::handleEvent(WebCore::ScriptExecutionContext&, WebCore::Event&) + 240 (JSEventListener.cpp:142) 4 WebCore 0x283b4ce20 WebCore::EventTarget::innerInvokeEventListeners(WebCore::Event&, WTF::Vector<WTF::RefPtr<WebCore::RegisteredEventListener, WTF::RawPtrTraits<WebCore::RegisteredEventListener>, WTF::DefaultRefDerefTraits<WebCore::RegisteredEventListener>>, 1ul, WTF::CrashOnOverflow, 2ul, WTF::FastMalloc>, WebCore::EventTarget::EventInvokePhase) + 1164 (EventTarget.cpp:372) 5 WebCore 0x283b4c7ec WebCore::EventTarget::fireEventListeners(WebCore::Event&, WebCore::EventTarget::EventInvokePhase) + 420 (EventTarget.cpp:304) 6 WebCore 0x283b4c634 WebCore::EventTarget::dispatchEvent(WebCore::Event&) + 360 (EventTarget.cpp:258) 7 WebCore 0x282b7ed38 WebCore::SpeechSynthesis::voicesDidChange() + 168 (SpeechSynthesis.cpp:93) 8 libWebCoreTestSupport.dylib 0x10bf19a0c WebCore::Internals::simulateSpeechSynthesizerVoicesListChange() + 100 (Internals.cpp:1577) 9 libWebCoreTestSupport.dylib 0x10c0d8570 WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChangeBody(JSC::JSGlobalObject*, JSC::CallFrame*, WebCore::JSInternals*)::'lambda'()::operator()() const + 32 (JSInternals.cpp:11353) 10 libWebCoreTestSupport.dylib 0x10c0d8538 JSC::JSValue WebCore::toJS<WebCore::IDLUndefined, WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChangeBody(JSC::JSGlobalObject*, JSC::CallFrame*, WebCore::JSInternals*)::'lambda'()>(JSC::JSGlobalObject&, JSC::ThrowScope&, WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChangeBody(JSC::JSGlobalObject*, JSC::CallFrame*, WebCore::JSInternals*)::'lambda'()&&) + 36 (JSDOMConvertBase.h:165) 11 libWebCoreTestSupport.dylib 0x10c0d84d8 WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChangeBody(JSC::JSGlobalObject*, JSC::CallFrame*, WebCore::JSInternals*) + 164 (JSInternals.cpp:11353) 12 libWebCoreTestSupport.dylib 0x10c0d840c long long WebCore::IDLOperation<WebCore::JSInternals>::call<&WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChangeBody(JSC::JSGlobalObject*, JSC::CallFrame*, WebCore::JSInternals*), (WebCore::CastedThisErrorBehavior)0>(JSC::JSGlobalObject&, JSC::CallFrame&, char const*) + 596 (JSDOMOperation.h:63) 13 libWebCoreTestSupport.dylib 0x10c05541c WebCore::jsInternalsPrototypeFunction_simulateSpeechSynthesizerVoicesListChange(JSC::JSGlobalObject*, JSC::CallFrame*) + 44 (JSInternals.cpp:11358)

Committed 267385@main (5eb9dd27dc3d): <https://commits.webkit.org/267385@main> Reviewed commits have been landed. Closing PR #16710 and removing active labels.