Bug 255206

[Win] WebGL tests are randomly failing an assertion: ASSERTION FAILED: ::IsWindow(m_runLoopMessageWindow)

WinCairo Debug is observing random assertion failures for WebGL tests these days.

In https://build.webkit.org/results/WinCairo-64-bit-Debug-Tests/262758@main%20(20089)/results.html
The log of webgl/2.0.y/conformance/rendering/color-mask-should-not-affect-antialiased-framebuffer-resolution.html contains two assertion failures.

ASSERTION FAILED: ::IsWindow(m_runLoopMessageWindow)
C:\BW\WinCairo-64-bit-Debug-Build\build\Source\WTF\wtf\win\RunLoopWin.cpp(109) : WTF::RunLoop::RunLoop
1   00007FFC1263249B WTFCrash
2   00007FFC126376BD WTFCrashWithInfo
3   00007FFC127CBBFF WTF::RunLoop::RunLoop
4   00007FFC126E2F2B WTF::RunLoop::Holder::Holder
5   00007FFC126E2E7C WTF::ThreadSpecific<WTF::RunLoop::Holder,0>::Data::Data
6   00007FFC126E5797 WTF::ThreadSpecific<WTF::RunLoop::Holder,0>::set
7   00007FFC126E3592 WTF::ThreadSpecific<WTF::RunLoop::Holder,0>::operator WTF::RunLoop::Holder *
8   00007FFC126E36B4 WTF::ThreadSpecific<WTF::RunLoop::Holder,0>::operator->
9   00007FFC126E03F3 WTF::RunLoop::current
10  00007FFC126E0D4F `WTF::RunLoop::create'::`2'::<lambda_1>::operator()
11  00007FFC126E0FEB WTF::Detail::CallableWrapper<`WTF::RunLoop::create'::`2'::<lambda_1>,void>::call
12  00007FFC1264A4F3 WTF::Function<void __cdecl(void)>::operator()
13  00007FFC126F0108 WTF::Thread::entryPoint
14  00007FFC127CD994 WTF::wtfThreadEntryPoint
15  00007FFC0A001FFA o_exp
16  00007FFC0B8F7974 BaseThreadInitThunk
17  00007FFC26DAA271 RtlUserThreadStart

ASSERTION FAILED: m_maxTransformFeedbackSeparateAttribs >= 4
C:\BW\WinCairo-64-bit-Debug-Build\build\Source\WebCore\html/canvas/WebGL2RenderingContext.cpp(163) : WebCore::WebGL2RenderingContext::initializeNewContext
1   00007FFC1263249B WTFCrash
2   00007FFBB4A9318E WTFCrashWithInfo
3   00007FFBB7C48ED2 WebCore::WebGL2RenderingContext::initializeNewContext
4   00007FFBB7C33DFD WebCore::WebGL2RenderingContext::create
5   00007FFBB7C8232A WebCore::WebGLRenderingContextBase::create
6   00007FFBB7A7359C WebCore::HTMLCanvasElement::createContextWebGL
7   00007FFBB7A72A6D WebCore::HTMLCanvasElement::getContext
8   00007FFBB562956E WebCore::jsHTMLCanvasElementPrototypeFunction_getContextBody
9   00007FFBB5632E25 WebCore::IDLOperation<WebCore::JSHTMLCanvasElement>::call<&WebCore::jsHTMLCanvasElementPrototypeFunction_getContextBody,0>
10  00007FFBB5627C75 WebCore::jsHTMLCanvasElementPrototypeFunction_getContext
11  000002DB800014DE (null)

That of webgl/2.0.0/conformance/typedarrays/typed-arrays-in-workers.html contains only "::IsWindow(m_runLoopMessageWindow)".