WKMouseDeviceObserver is calling WebProcessProxy::send() on a non-main thread on iOS. WebProcessProxy::send() is not thread-safe so we added an assertion in r275839 to help catch such bugs.
<rdar://76598710>
Created attachment 425952 [details] Patch
Found 1 new test failure: imported/w3c/web-platform-tests/webaudio/the-audio-api/the-mediastreamaudiosourcenode-interface/mediastreamaudiosourcenode-ctor.html
Comment on attachment 425952 [details] Patch Nonsense.
Committed r275937 (236499@main): <https://commits.webkit.org/236499@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 425952 [details].