Clear old decoders after recreating the receiver.

talk/media/webrtc/webrtcvideoengine2.cc

Index: talk/media/webrtc/webrtcvideoengine2.cc
diff --git a/talk/media/webrtc/webrtcvideoengine2.cc b/talk/media/webrtc/webrtcvideoengine2.cc
index 308b68b4574d52c5b8e865aaca118c27ea7d1dda..844b118527f7f22faba2af0646b24dcdaff63c20 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -2376,10 +2376,10 @@ void WebRtcVideoChannel2::WebRtcVideoReceiveStream::SetRecvCodecs(
   config_.rtp.nack.rtp_history_ms =
       HasNack(recv_codecs.begin()->codec) ? kNackHistoryMs : 0;
 
-  ClearDecoders(&old_decoders);
   LOG(LS_INFO) << "RecreateWebRtcStream (recv) because of SetRecvCodecs: "
                << CodecSettingsVectorToString(recv_codecs);
   RecreateWebRtcStream();
+  ClearDecoders(&old_decoders);
 }
 
 void WebRtcVideoChannel2::WebRtcVideoReceiveStream::SetLocalSsrc(