Add a VideoCoding::RegisterReceiveCodec method with payload_type

Intended to ease removal of VideoCodec::plType, separating video
coding from transport.

Bug: None
Change-Id: I0764f2f714eab9ee4c3e55751819cd5915fb37b6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181075
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31892}

modules/video_coding/decoder_database.h

@@ -45,7 +45,8 @@ class VCMDecoderDataBase {
   void RegisterExternalDecoder(VideoDecoder* external_decoder,
                                uint8_t payload_type);
 
-  bool RegisterReceiveCodec(const VideoCodec* receive_codec,
+  bool RegisterReceiveCodec(uint8_t payload_type,
+                            const VideoCodec* receive_codec,
                             int number_of_cores);
   bool DeregisterReceiveCodec(uint8_t payload_type);