Refactoring PayloadRouter.

- Move PayloadRouter to RtpTransportControllerInterface.
- Move RetransmissionLimiter inside RtpTransportControllerSend from
  VideoSendStreamImpl.
- Move video RTP specifics into PayloadRouter, in particular ownership
  of the RTP modules.
- PayloadRouter now contains all video specific RTP code, and will be
  renamed in a follow-up to VideoRtpSender.
- Introduce VideoRtpSenderInterface.

Bug: webrtc:9517
Change-Id: I1c7b293fa6f9c320286c80533b3c584498034a38
Reviewed-on: https://webrtc-review.googlesource.com/88240
Commit-Queue: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24009}
diff --git a/modules/video_coding/decoder_database.cc b/modules/video_coding/decoder_database.cc
index 908a94a..9cb7823 100644
--- a/modules/video_coding/decoder_database.cc
+++ b/modules/video_coding/decoder_database.cc
@@ -29,6 +29,8 @@
     : payload_type(payload_type),
       external_decoder_instance(external_decoder_instance) {}
 
+VCMDecoderMapItem::~VCMDecoderMapItem() {}
+
 VCMDecoderDataBase::VCMDecoderDataBase()
     : receive_codec_(), dec_map_(), dec_external_map_() {}