Remove NullObjectReceiveStatistics() in rtp_rtcp module

webrtc/modules/rtp_rtcp/source/rtp_utility.h

 /*
  *  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.
  */
 
 #ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_UTILITY_H_
 #define WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_UTILITY_H_
 
 #include <map>
 
 #include "webrtc/modules/rtp_rtcp/include/receive_statistics.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_header_extension_map.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_rtcp_config.h"
 #include "webrtc/rtc_base/deprecation.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 const uint8_t kRtpMarkerBitMask = 0x80;
 
 RtpFeedback* NullObjectRtpFeedback();
-ReceiveStatistics* NullObjectReceiveStatistics();
 
 namespace RtpUtility {
 
 struct Payload {
   char name[RTP_PAYLOAD_NAME_SIZE];
   bool audio;
   PayloadUnion typeSpecific;
 };
 
 bool StringCompare(const char* str1, const char* str2, const uint32_t length);
@@ skipping 17 matching lines @@
                                    const uint8_t* ptrRTPDataExtensionEnd,
                                    const uint8_t* ptr) const;
 
   const uint8_t* const _ptrRTPDataBegin;
   const uint8_t* const _ptrRTPDataEnd;
 };
 }  // namespace RtpUtility
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_UTILITY_H_