[VideoStream] resource for WebM videos. [VideoStream] resource handling the [url=https://www.webmproject.org/]WebM[/url] video format with [code].webm[/code] extension. Returns the WebM video file handled by this [VideoStreamWebm]. Sets the WebM video file that this [VideoStreamWebm] resource handles. The [code]file[/code] name should have the [code].webm[/code] extension.