Minor updates to WebRTC Video Engine

Removes unused member variables (bitrate_allocator_factory_,
worker_thread_) and unused functions (SetFeedbackParameters,
flexfec_stream(), stream()).

Bug: none
Change-Id: I4f668fe2a2facd47bfa56e4a17acc465908ee370
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/472160
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47702}

media/engine/webrtc_video_engine.cc

diff --git a/media/engine/webrtc_video_engine.cc b/media/engine/webrtc_video_engine.cc
index 2d184c4..640ca8d 100644
--- a/media/engine/webrtc_video_engine.cc
+++ b/media/engine/webrtc_video_engine.cc
@@ -1860,7 +1860,6 @@
     const VideoSenderParameters& send_params)
     : send_channel_(send_channel),
       env_(env),
-      worker_thread_(call->worker_thread()),
       ssrcs_(sp.ssrcs),
       ssrc_groups_(sp.ssrc_groups),
       call_(call),
@@ -2851,7 +2850,6 @@
     VideoDecoderFactory* decoder_factory)
     : MediaChannelUtil(call->network_thread(), config.enable_dscp),
       env_(env),
-      worker_thread_(call->worker_thread()),
       network_thread_safety_(PendingTaskSafetyFlag::CreateAttachedToTaskQueue(
           /*alive=*/true,
           call->network_thread())),
@@ -3532,16 +3530,7 @@
     call_->DestroyFlexfecReceiveStream(flexfec_stream_);
 }
 
-VideoReceiveStreamInterface&
-WebRtcVideoReceiveChannel::WebRtcVideoReceiveStream::stream() {
-  RTC_DCHECK(stream_);
-  return *stream_;
-}
 
-FlexfecReceiveStream*
-WebRtcVideoReceiveChannel::WebRtcVideoReceiveStream::flexfec_stream() {
-  return flexfec_stream_;
-}
 
 const std::vector<uint32_t>&
 WebRtcVideoReceiveChannel::WebRtcVideoReceiveStream::GetSsrcs() const {

media/engine/webrtc_video_engine.h

diff --git a/media/engine/webrtc_video_engine.h b/media/engine/webrtc_video_engine.h
index d9206d0..d19ca1c 100644
--- a/media/engine/webrtc_video_engine.h
+++ b/media/engine/webrtc_video_engine.h
@@ -144,8 +144,6 @@
  private:
   const std::unique_ptr<VideoDecoderFactory> decoder_factory_;
   const std::unique_ptr<VideoEncoderFactory> encoder_factory_;
-  const std::unique_ptr<VideoBitrateAllocatorFactory>
-      bitrate_allocator_factory_;
   const FieldTrialsView& trials_;  // from PeerConnectionFactory
 };
 
@@ -408,7 +406,6 @@
     WebRtcVideoSendChannel* const send_channel_;
     const Environment env_;
     RTC_NO_UNIQUE_ADDRESS SequenceChecker thread_checker_;
-    TaskQueueBase* const worker_thread_;
     const std::vector<uint32_t> ssrcs_ RTC_GUARDED_BY(&thread_checker_);
     const std::vector<SsrcGroup> ssrc_groups_ RTC_GUARDED_BY(&thread_checker_);
     Call* const call_;
@@ -624,10 +621,6 @@
         const FlexfecReceiveStream::Config& flexfec_config);
     ~WebRtcVideoReceiveStream() override;
 
-    VideoReceiveStreamInterface& stream();
-    // Return value may be nullptr.
-    FlexfecReceiveStream* flexfec_stream();
-
     const std::vector<uint32_t>& GetSsrcs() const;
 
     std::vector<RtpSource> GetSources();
@@ -636,11 +629,6 @@
     // owning WebRtcVideoChannel.
     RtpParameters GetRtpParameters() const;
 
-    // TODO(deadbeef): Move these feedback parameters into the recv parameters.
-    void SetFeedbackParameters(bool lntf_enabled,
-                               bool nack_enabled,
-                               RtcpMode rtcp_mode,
-                               std::optional<int> rtx_time);
     void SetReceiverParameters(const ChangedReceiverParameters& recv_params);
 
     void OnFrame(const VideoFrame& frame) override;
@@ -724,7 +712,6 @@
   }
   // Variables.
   const Environment env_;
-  TaskQueueBase* const worker_thread_;
   ScopedTaskSafety task_safety_;
   scoped_refptr<PendingTaskSafetyFlag> network_thread_safety_;
   RTC_NO_UNIQUE_ADDRESS SequenceChecker network_thread_checker_{