[TrackConfiguration] Why not reuse WebCodec's configuration dictionaries?

[dalecurtis]

Instead of implementing new AudioTrackConfiguration and VideoTrackConfiguration dictionaries, can the corresponding AudioDecoderConfig and VideoDecoderConfig dictionaries from WebCodecs be reused?

The top requests we've gotten from developers are:

• What the heck is a codec string?
• How do I fill in AVC/HEVC description fields?

As a stop gap to providing a containers API, having this information available via tracks seems helpful.

Thanks for suggesting the API!