Capture state of the microphone device. Whenever the user grants a media-request sent by the web page, requesting audio capture capabilities (`navigator.mediaDevices.getUserMedia({audio: true})`) this property will be set to webkit.types.MediaCaptureState.Active.
The application can monitor this property and provide a visual indicator allowing to optionally deactivate or mute the capture device by setting this property respectively to webkit.types.MediaCaptureState.None or webkit.types.MediaCaptureState.Muted.
If the capture state of the device is set to webkit.types.MediaCaptureState.None the web-page can still re-request the permission to the user. Permission desision caching is left to the application.
Set microphoneCaptureState property.