Prepare for deleting VideoCodec::plType

Deletes all webrtc usage of this member. Next step is to delete
any downstream references, and when that's done, the member can be
deleted.

Bug: None
Change-Id: I3f3a94a063dccf56468a1069653efd3809875b01
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181201
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31911}

video/rtp_video_stream_receiver2.cc

diff --git a/video/rtp_video_stream_receiver2.cc b/video/rtp_video_stream_receiver2.cc
index 3f11bb7..1a53165 100644
--- a/video/rtp_video_stream_receiver2.cc
+++ b/video/rtp_video_stream_receiver2.cc
@@ -326,15 +326,16 @@
 }
 
 void RtpVideoStreamReceiver2::AddReceiveCodec(
+    uint8_t payload_type,
     const VideoCodec& video_codec,
     const std::map<std::string, std::string>& codec_params,
     bool raw_payload) {
   RTC_DCHECK_RUN_ON(&worker_task_checker_);
   payload_type_map_.emplace(
-      video_codec.plType,
-      raw_payload ? std::make_unique<VideoRtpDepacketizerRaw>()
-                  : CreateVideoRtpDepacketizer(video_codec.codecType));
-  pt_codec_params_.emplace(video_codec.plType, codec_params);
+      payload_type, raw_payload
+                        ? std::make_unique<VideoRtpDepacketizerRaw>()
+                        : CreateVideoRtpDepacketizer(video_codec.codecType));
+  pt_codec_params_.emplace(payload_type, codec_params);
 }
 
 absl::optional<Syncable::Info> RtpVideoStreamReceiver2::GetSyncInfo() const {