Reland "Remove AudioReceiveStream::Reconfigure() method."

This reverts commit 8a18e5b3c954a3f9cc006c90356a3d850bcc352f.

Reason for revert: Removing the problematic DCHECK.

Original change's description:
> Revert "Remove AudioReceiveStream::Reconfigure() method."
>
> This reverts commit e2561e17e29e62c02731f1d214d7ee5ffdaeb941.
>
> Reason for revert: Speculative revert: breaks an downstream project
>
> Original change's description:
> > Remove AudioReceiveStream::Reconfigure() method.
> >
> > Instead, adding specific setters that are needed at runtime:
> > * SetDepacketizerToDecoderFrameTransformer
> > * SetDecoderMap
> > * SetUseTransportCcAndNackHistory
> >
> > The whole config struct is big and much of the state it holds, needs to
> > be considered const. For that reason the Reconfigure() method is too
> > broad of an interface since it overwrites the whole config struct
> > and doesn't actually handle all the potential config changes that might
> > occur when the config changes.
> >
> > Bug: webrtc:11993
> > Change-Id: Ia5311978f56b2e136781467e44f0d18039f0bb2d
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/221363
> > Reviewed-by: Niels Moller <nisse@webrtc.org>
> > Commit-Queue: Tommi <tommi@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#34252}
>
> TBR=saza@webrtc.org,nisse@webrtc.org,tommi@webrtc.org,webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com
>
> Change-Id: I15ca2d8ee5fd612e13dc1f4b3bfb9c885c21dc66
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: webrtc:11993
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/221746
> Commit-Queue: Artem Titov <titovartem@webrtc.org>
> Reviewed-by: Andrey Logvin <landrey@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#34253}

# Not skipping CQ checks because this is a reland.

Bug: webrtc:11993
Change-Id: I0d3bf9abdcdc8d3f9259d014e6074a5e6b6cc73c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/221747
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Andrey Logvin <landrey@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34255}

audio/audio_receive_stream.h

@@ -11,6 +11,7 @@
 #ifndef AUDIO_AUDIO_RECEIVE_STREAM_H_
 #define AUDIO_AUDIO_RECEIVE_STREAM_H_
 
+#include <map>
 #include <memory>
 #include <vector>
 
@@ -81,10 +82,15 @@ class AudioReceiveStream final : public webrtc::AudioReceiveStream,
   void UnregisterFromTransport();
 
   // webrtc::AudioReceiveStream implementation.
-  void Reconfigure(const webrtc::AudioReceiveStream::Config& config) override;
   void Start() override;
   void Stop() override;
   bool IsRunning() const override;
+  void SetDepacketizerToDecoderFrameTransformer(
+      rtc::scoped_refptr<webrtc::FrameTransformerInterface> frame_transformer)
+      override;
+  void SetDecoderMap(std::map<int, SdpAudioFormat> decoder_map) override;
+  void SetUseTransportCcAndNackHistory(bool use_transport_cc,
+                                       int history_ms) override;
 
   webrtc::AudioReceiveStream::Stats GetStats(
       bool get_and_clear_legacy_stats) const override;
@@ -111,9 +117,25 @@ class AudioReceiveStream final : public webrtc::AudioReceiveStream,
 
   void AssociateSendStream(AudioSendStream* send_stream);
   void DeliverRtcp(const uint8_t* packet, size_t length);
+
+  uint32_t local_ssrc() const {
+    // The local_ssrc member variable of config_ will never change and can be
+    // considered const.
+    return config_.rtp.local_ssrc;
+  }
+
+  uint32_t remote_ssrc() const {
+    // The remote_ssrc member variable of config_ will never change and can be
+    // considered const.
+    return config_.rtp.remote_ssrc;
+  }
+
   const webrtc::AudioReceiveStream::Config& config() const;
   const AudioSendStream* GetAssociatedSendStreamForTesting() const;
 
+  // TODO(tommi): Remove this method.
+  void ReconfigureForTesting(const webrtc::AudioReceiveStream::Config& config);
+
  private:
   AudioState* audio_state() const;