Stop leaking FlexfecReceiveStream objects after call shutdown.

webrtc/media/engine/webrtcvideoengine2.cc

 /*
  *  Copyright (c) 2014 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 2108 matching lines @@
       type(type),
       external(external) {
   if (external) {
     external_decoder = decoder;
     this->decoder =
         new webrtc::VideoDecoderSoftwareFallbackWrapper(type, external_decoder);
   }
 }
 
 WebRtcVideoChannel2::WebRtcVideoReceiveStream::~WebRtcVideoReceiveStream() {
+  if (flexfec_stream_) {
+    call_->DestroyFlexfecReceiveStream(flexfec_stream_);
+  }
   call_->DestroyVideoReceiveStream(stream_);
   ClearDecoders(&allocated_decoders_);
 }
 
 const std::vector<uint32_t>&
 WebRtcVideoChannel2::WebRtcVideoReceiveStream::GetSsrcs() const {
   return stream_params_.ssrcs;
 }
 
 rtc::Optional<uint32_t>
@@ skipping 373 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             ulpfec_config.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket