message: New struct SimulcastStream.
  Currently has the same contents as struct SpatialLayer. Intention is
  to add a ScalabilityMode member, which isn't appropriate for a spatial
  layer.
  Cr-Commit-Position: refs/heads/main@{#37062}
diff: #ifndef API_VIDEO_CODECS_SIMULCAST_STREAM_H_
  #define API_VIDEO_CODECS_SIMULCAST_STREAM_H_
  -#include "api/video_codecs/spatial_layer.h"
  -
  namespace webrtc {
  // TODO(bugs.webrtc.org/6883): Unify with struct VideoStream, part of
  // VideoEncoderConfig.
  -// TODO(bugs.webrtc.org/11607): Make this a separate type, rather than an alias.
  -using SimulcastStream = SpatialLayer;
  +struct SimulcastStream {
  + int width;
  + int height;
  + float maxFramerate; // fps.
  + unsigned char numberOfTemporalLayers;
  + unsigned int maxBitrate; // kilobits/sec.
  + unsigned int targetBitrate; // kilobits/sec.
  + unsigned int minBitrate; // kilobits/sec.
  + unsigned int qpMax; // minimum quality
  + bool active; // encoded and sent.
  +};
  } // namespace webrtc
  #endif // API_VIDEO_CODECS_SIMULCAST_STREAM_H_
  