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/neteq/decoder_database.h

@@ -149,6 +149,11 @@ class DecoderDatabase {
   // using InsertExternal().
   virtual void Reset();
 
+  // Replaces the existing set of decoders with the given set. Returns the
+  // payload types that were reassigned or removed while doing so.
+  virtual std::vector<int> SetCodecs(
+      const std::map<int, SdpAudioFormat>& codecs);
+
   // Registers |rtp_payload_type| as a decoder of type |codec_type|. The |name|
   // is only used to populate the name field in the DecoderInfo struct in the
   // database, and can be arbitrary (including empty). Returns kOK on success;