Add mimeType option: audio/webm;codecs=pcm (#47378)
Add mimeType option: audio/webm;codecs=pcm (#47378)


georgemarshall/DefinitelyTyped,markogresak/DefinitelyTyped,georgemarshall/DefinitelyTyped,mcliment/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped