Fix bug where rtcp::TransportFeedback may generate incorrect messages.

webrtc/modules/rtp_rtcp/source/rtcp_utility.cc

Index: webrtc/modules/rtp_rtcp/source/rtcp_utility.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_utility.cc b/webrtc/modules/rtp_rtcp/source/rtcp_utility.cc
index 6c1deb467ef787de5947df7d70ef4384c56204fd..d2b80438cccbacc877da088cd9fdda5854841c9a 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_utility.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_utility.cc
@@ -1235,13 +1235,13 @@ bool RTCPUtility::RTCPParserV2::ParseFBCommon(const RtcpCommonHeader& header) {
             return true;
         }
         case 15: {
-          _packetType = RTCPPacketTypes::kTransportFeedback;
           rtcp_packet_ =
               rtcp::TransportFeedback::ParseFrom(_ptrRTCPData - 12, length);
           // Since we parse the whole packet here, keep the TopLevel state and
           // just end the current block.
+          EndCurrentBlock();
           if (rtcp_packet_.get()) {
-            EndCurrentBlock();
+            _packetType = RTCPPacketTypes::kTransportFeedback;
             return true;
           }
           break;