Delete class SSRCDatabase, and its global ssrc registry.

webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
index 3c986e98c210e62bc171c98b13be4c6b1c51b0d9..29476d0fd7b05ffd42e5be27c94b6e19ef8cd03b 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
@@ -100,7 +100,6 @@ ModuleRtpRtcpImpl::ModuleRtpRtcpImpl(const Configuration& configuration)
                      this),
       clock_(configuration.clock),
       audio_(configuration.audio),
-      collision_detected_(false),
       last_process_time_(configuration.clock->TimeInMilliseconds()),
       last_bitrate_process_time_(configuration.clock->TimeInMilliseconds()),
       last_rtt_process_time_(configuration.clock->TimeInMilliseconds()),
@@ -356,8 +355,6 @@ int32_t ModuleRtpRtcpImpl::SetSendingStatus(const bool sending) {
       LOG(LS_WARNING) << "Failed to send RTCP BYE";
     }
 
-    collision_detected_ = false;
-
     // Generate a new SSRC for the next "call" if false

[nisse-webrtc, 2017/01/31 14:23:42]

This is no longer true, the SetSendingStatus is a nop. 

Is this feature used for anything? If we need to select a new ssrc, where should
that allocation move?

[nisse-webrtc, 2017/02/01 10:52:50]

I just deleted this function and the below logic. It was used only for automatic
ssrc selection.

     rtp_sender_.SetSendingStatus(sending);
 
@@ -785,24 +782,6 @@ void ModuleRtpRtcpImpl::SetRemoteSSRC(const uint32_t ssrc) {
   // Inform about the incoming SSRC.
   rtcp_sender_.SetRemoteSSRC(ssrc);
   rtcp_receiver_.SetRemoteSSRC(ssrc);
-
-  // Check for a SSRC collision.
-  if (rtp_sender_.SSRC() == ssrc && !collision_detected_) {
-    // If we detect a collision change the SSRC but only once.
-    collision_detected_ = true;
-    uint32_t new_ssrc = rtp_sender_.GenerateNewSSRC();
-    if (new_ssrc == 0) {
-      // Configured via API ignore.
-      return;
-    }
-    if (RtcpMode::kOff != rtcp_sender_.Status()) {
-      // Send RTCP bye on the current SSRC.
-      SendRTCP(kRtcpBye);
-    }
-    // Change local SSRC and inform all objects about the new SSRC.
-    rtcp_sender_.SetSSRC(new_ssrc);
-    SetRtcpReceiverSsrcs(new_ssrc);
-  }
 }
 
 void ModuleRtpRtcpImpl::BitrateSent(uint32_t* total_rate,