Remove unused members from WebRtcVoiceEngine and channels

This cleanup removes member variables that were declared but never
used in the implementation, likely as a result of previous
refactorings or the send/receive channel split.

- WebRtcVoiceEngine: removes is_dumping_aec_
- WebRtcVoiceSendChannel: removes unsignaled_frame_transformer_
- WebRtcVoiceReceiveChannel: removes send_codec_spec_

Bug: None
Change-Id: I555ceca1b72f8d0f1d9e79b92945fda6850fc2bf
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/455200
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Tomas Gunnarsson <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47091}
diff --git a/media/engine/webrtc_voice_engine.h b/media/engine/webrtc_voice_engine.h
index 0100fc4..97907fd 100644
--- a/media/engine/webrtc_voice_engine.h
+++ b/media/engine/webrtc_voice_engine.h
@@ -162,7 +162,6 @@
   scoped_refptr<AudioState> audio_state_ RTC_GUARDED_BY(worker_thread_checker_);
   const std::vector<Codec> legacy_send_codecs_;
   const std::vector<Codec> legacy_recv_codecs_;
-  bool is_dumping_aec_ RTC_GUARDED_BY(worker_thread_checker_) = false;
   bool initialized_ RTC_GUARDED_BY(worker_thread_checker_) = false;
 
   // Jitter buffer settings for new streams.
@@ -304,8 +303,6 @@
   // Per peer connection crypto options that last for the lifetime of the peer
   // connection.
   const CryptoOptions crypto_options_;
-  scoped_refptr<FrameTransformerInterface> unsignaled_frame_transformer_
-      RTC_GUARDED_BY(worker_thread_);
 
   // Callback invoked whenever the list of SSRCs changes.
   absl::AnyInvocable<void(const std::set<uint32_t>&)>
@@ -466,9 +463,6 @@
 
   AudioReceiverParameters recv_params_ RTC_GUARDED_BY(worker_thread_);
 
-  std::optional<AudioSendStream::Config::SendCodecSpec> send_codec_spec_
-      RTC_GUARDED_BY(worker_thread_);
-
   // Per peer connection crypto options that last for the lifetime of the peer
   // connection.
   const CryptoOptions crypto_options_;