WebRtcVoiceMediaChannel::AddRecvStream: Don't call SetRecPayloadType

This removes one more place where we were unable to handle codecs not
in the built-in set.

BUG=webrtc:5805

Review-Url: https://codereview.webrtc.org/2686043006
Cr-Commit-Position: refs/heads/master@{#17370}

webrtc/modules/audio_coding/include/audio_coding_module.h

@@ -485,6 +485,10 @@ class AudioCodingModule {
   //
   virtual int32_t PlayoutFrequency() const = 0;
 
+  // Replace any existing decoders with the given payload type -> decoder map.
+  virtual void SetReceiveCodecs(
+      const std::map<int, SdpAudioFormat>& codecs) = 0;
+
   // Registers a decoder for the given payload type. Returns true iff
   // successful.
   virtual bool RegisterReceiveCodec(int rtp_payload_type,