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

webrtc/modules/rtp_rtcp/source/rtcp_utility.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 1217 matching lines @@
          {
             // RTCP-SR-REQ Rapid Synchronisation of RTP Flows
             // draft-perkins-avt-rapid-rtp-sync-03.txt
             // trigger a new RTCP SR
           _packetType = RTCPPacketTypes::kRtpfbSrReq;
 
             // Note: No state transition, SR REQ is empty!
             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;
         }
         default:
             break;
         }
         // Unsupported RTPFB message. Skip and move to next block.
         ++num_skipped_blocks_;
         return false;
@@ skipping 448 matching lines @@
 const RTCPUtility::RtcpCommonHeader*
 RTCPUtility::RTCPPacketIterator::Current() {
     if (!_ptrBlock)
     {
         return NULL;
     }
 
     return &_header;
 }
 }  // namespace webrtc