What can't loopback test be more like full stack test?

webrtc/video/video_quality_test.h

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #ifndef WEBRTC_VIDEO_VIDEO_QUALITY_TEST_H_
@@ skipping 77 matching lines @@
     int num_thumbnails;
   };
 
   VideoQualityTest();
   void RunWithAnalyzer(const Params& params);
   void RunWithRenderers(const Params& params);
 
   static void FillScalabilitySettings(
       Params* params,
       const std::vector<std::string>& stream_descriptors,
+      int num_streams,
       size_t selected_stream,
       int num_spatial_layers,
       int selected_sl,
       const std::vector<std::string>& sl_descriptors);
 
  protected:
   std::map<uint8_t, webrtc::MediaType> payload_type_map_;
 
   // No-op implementation to be able to instantiate this class from non-TEST_F
   // locations.
@@ skipping 10 matching lines @@
 
   // Helper methods for setting up the call.
   void CreateCapturer();
   void SetupThumbnailCapturers(size_t num_thumbnail_streams);
   void SetupVideo(Transport* send_transport, Transport* recv_transport);
   void SetupThumbnails(Transport* send_transport, Transport* recv_transport);
   void DestroyThumbnailStreams();
   void SetupScreenshareOrSVC();
   void SetupAudio(int send_channel_id,
                   int receive_channel_id,
-                  Call* call,
                   Transport* transport,
                   AudioReceiveStream** audio_receive_stream);
 
   void StartEncodedFrameLogs(VideoSendStream* stream);
   void StartEncodedFrameLogs(VideoReceiveStream* stream);
 
   // We need a more general capturer than the FrameGeneratorCapturer.
   std::unique_ptr<test::VideoCapturer> video_capturer_;
   std::vector<std::unique_ptr<test::VideoCapturer>> thumbnail_capturers_;
   std::unique_ptr<test::TraceToStderr> trace_to_stderr_;
@@ skipping 14 matching lines @@
   int send_logs_;
 
   VideoSendStream::DegradationPreference degradation_preference_ =
       VideoSendStream::DegradationPreference::kMaintainFramerate;
   Params params_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_VIDEO_QUALITY_TEST_H_