Bug 1339270: Add rtp 'padding' packets into rtp history for handling NACKs r=ng

Webrtc.org issue 7143:
https://bugs.chromium.org/p/webrtc/issues/detail?id=7143

MozReview-Commit-ID: 9pGj63gWSC6

media/webrtc/trunk/webrtc/modules/rtp_rtcp/source/rtp_sender.cc

@@ -702,6 +702,11 @@ size_t RTPSender::SendPadData(size_t bytes,
       transport_feedback_observer_->AddPacket(options.packet_id, length, true);
     }
 
+    if (packet_history_.PutRTPPacket(padding_packet, length,
+                                     capture_time_ms,
+                                     kAllowRetransmission) != 0) {
+      return 0;
+    }
     if (!SendPacketToNetwork(padding_packet, length, options))
       break;