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/session_info.h b/modules/video_coding/session_info.h
index 0b8fd69..b845ffb 100644
--- a/modules/video_coding/session_info.h
+++ b/modules/video_coding/session_info.h
@@ -30,6 +30,7 @@
 class VCMSessionInfo {
  public:
   VCMSessionInfo();
+  ~VCMSessionInfo();
 
   void UpdateDataPointers(const uint8_t* old_base_ptr,
                           const uint8_t* new_base_ptr);