text: // Copyright 2021 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef REMOTING_PROTOCOL_WEBRTC_VIDEO_TRACK_SOURCE_H_
  #define REMOTING_PROTOCOL_WEBRTC_VIDEO_TRACK_SOURCE_H_
  
  #include "base/callback.h"
  #include "base/task/sequenced_task_runner.h"
  #include "remoting/codec/webrtc_video_encoder.h"
  #include "third_party/webrtc/api/media_stream_interface.h"
  #include "third_party/webrtc/api/notifier.h"
  #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
  
  #include <memory>
  
  namespace remoting {
  namespace protocol {
  
  class WebrtcVideoTrackSource
      : public webrtc::Notifier<webrtc::VideoTrackSourceInterface> {
   public:
    // |add_sink_callback| is notified on the main thread whenever a sink is
    // added or updated.
    explicit WebrtcVideoTrackSource(base::RepeatingClosure add_sink_callback);
    ~WebrtcVideoTrackSource() override;
    WebrtcVideoTrackSource(const WebrtcVideoTrackSource&) = delete;
    WebrtcVideoTrackSource& operator=(const WebrtcVideoTrackSource&) = delete;
  
    // VideoTrackSourceInterface implementation.
    SourceState state() const override;
    bool remote() const override;
    bool is_screencast() const override;
    absl::optional<bool> needs_denoising() const override;
    bool GetStats(Stats* stats) override;
    void AddOrUpdateSink(rtc::VideoSinkInterface<webrtc::VideoFrame>* sink,
                         const rtc::VideoSinkWants& wants) override;
    void RemoveSink(rtc::VideoSinkInterface<webrtc::VideoFrame>* sink) override;
    bool SupportsEncodedOutput() const override;
    void GenerateKeyFrame() override;
    void AddEncodedSink(
        rtc::VideoSinkInterface<webrtc::RecordableEncodedFrame>* sink) override;
    void RemoveEncodedSink(
        rtc::VideoSinkInterface<webrtc::RecordableEncodedFrame>* sink) override;
  
    // Sends a captured frame to the sink if one was added. The |frame_stats|
    // will be associated with the frame and will be attached to the output
    // EncodedFrame.
    void SendCapturedFrame(
        std::unique_ptr<webrtc::DesktopFrame> desktop_frame,
        std::unique_ptr<WebrtcVideoEncoder::FrameStats> frame_stats);
  
   private:
    rtc::VideoSinkInterface<webrtc::VideoFrame>* sink_ = nullptr;
    base::RepeatingClosure add_sink_callback_;
    scoped_refptr<base::SequencedTaskRunner> main_task_runner_;
  
    // Incrementing ID to be attached to each VideoFrame, so that the
    // encoder-wrapper can detect if a frame was dropped.
    uint16_t frame_id_ = 0;
  };
  
  }  // namespace protocol
  }  // namespace remoting
  
  #endif  // REMOTING_PROTOCOL_WEBRTC_VIDEO_TRACK_SOURCE_H_
  