Wire up rtcp xr target bitrate on receive side.

webrtc/test/fuzzers/rtcp_receiver_fuzzer.cc

 /*
  *  Copyright (c) 2015 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.
  */
 #include "webrtc/base/checks.h"
@@ skipping 11 matching lines @@
   void OnReceivedRtcpReportBlocks(const ReportBlockList&) override {};
 };
 
 }
 
 void FuzzOneInput(const uint8_t* data, size_t size) {
   NullModuleRtpRtcp rtp_rtcp_module;
   SimulatedClock clock(1234);
 
   RTCPReceiver receiver(&clock, false, nullptr, nullptr, nullptr, nullptr,
-                        &rtp_rtcp_module);
+                        nullptr, &rtp_rtcp_module);
 
   receiver.IncomingPacket(data, size);
 }
 }  // namespace webrtc