Use separate rtp module lists for send and receive in PacketRouter.

webrtc/modules/pacing/packet_router.h

Index: webrtc/modules/pacing/packet_router.h
diff --git a/webrtc/modules/pacing/packet_router.h b/webrtc/modules/pacing/packet_router.h
index edef1aa9b3f89618b6c33625487225aebac26c88..0de23dc787349d41f3c7c1a4ea4d0a3eb1f09309 100644
--- a/webrtc/modules/pacing/packet_router.h
+++ b/webrtc/modules/pacing/packet_router.h
@@ -36,8 +36,8 @@ class PacketRouter : public PacedSender::Callback,
   PacketRouter();
   virtual ~PacketRouter();
 
-  void AddRtpModule(RtpRtcp* rtp_module);
-  void RemoveRtpModule(RtpRtcp* rtp_module);
+  void AddRtpModule(RtpRtcp* rtp_module, bool sender);
+  void RemoveRtpModule(RtpRtcp* rtp_module, bool sender);
 
   // Implements PacedSender::Callback.
   bool TimeToSendPacket(uint32_t ssrc,
@@ -54,9 +54,10 @@ class PacketRouter : public PacedSender::Callback,
   virtual bool SendFeedback(rtcp::TransportFeedback* packet);
 
  private:
-  rtc::CriticalSection modules_lock_;
-  // Map from ssrc to sending rtp module.
-  std::list<RtpRtcp*> rtp_modules_ GUARDED_BY(modules_lock_);
+  rtc::CriticalSection send_modules_crit_;
+  rtc::CriticalSection recv_modules_crit_;
+  std::list<RtpRtcp*> send_rtp_modules_ GUARDED_BY(send_modules_crit_);
+  std::list<RtpRtcp*> recv_rtp_modules_ GUARDED_BY(recv_modules_crit_);
 
   volatile int transport_seq_;