https://w3c.github.io/mediacapture-main/#media-track-constraints
<rdar://problem/27776658>
Created attachment 285697 [details] Patch
Comment on attachment 285697 [details] Patch Given how complex these dictionaries are and the way they are used, I feel it may be simpler for now to not bother with dictionaries at all in the IDL. We could just mark getConstaints() and applyConstraints() as [Custom] in the IDL (not declare any dictionaries in the IDL) and convert and do the JSValue <-> Internal Class conversion in the custom bindings. This way, you can declare your internal MediaTrackContraints class whatever way you like and make it convenient to use on native side. I think it is going to be a while until we can support such complex dictionaries in the bindings generator and the current struct it is able to generate is not very useful to us on native side and is very inconvenient to use.
OK, it does seem like the dictionary MediaTrackConstraintSet and MediaTrackConstraints will not help us all that much in parsing the data. Doing it in Custom works.