anchor.diff:  ///
   ///  * https://www.w3.org/TR/webcodecs/#imagedecoder-interface
   @JS('window.ImageDecoder')
  +@staticInterop
   class ImageDecoder {
  -  external ImageDecoder(ImageDecoderOptions options);
  +  external factory ImageDecoder(ImageDecoderOptions options);
  +}
  +
  +extension ImageDecoderExtension on ImageDecoder {
     external ImageTrackList get tracks;
     external bool get complete;
     external JsPromise decode(DecodeOptions options);
  
positive.code: ///  * https://www.w3.org/TR/webcodecs/#imagetrack
  @JS()
  @anonymous
  class ImageTrack {
    external int get repetitionCount;
    external int get frameCount;
  }
  
negative.code: ///  * https://www.w3.org/TR/webcodecs/#dictdef-imagedecodeoptions
  @JS()
  @anonymous
  @staticInterop
  class DecodeOptions {
    external factory DecodeOptions({
      required int frameIndex,
  