Allow parsing empty RTCP TargetBitrate messages, but stop sending them.

webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.h

 /*
  *  Copyright (c) 2016 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 27 matching lines @@
 
   TargetBitrate();
   ~TargetBitrate();
 
   void AddTargetBitrate(uint8_t spatial_layer,
                         uint8_t temporal_layer,
                         uint32_t target_bitrate_kbps);
 
   const std::vector<BitrateItem>& GetTargetBitrates() const;
 
-  bool Parse(const uint8_t* block, uint16_t block_length);
+  void Parse(const uint8_t* block, uint16_t block_length);
 
   size_t BlockLength() const;
 
   void Create(uint8_t* buffer) const;
 
  private:
   std::vector<BitrateItem> bitrates_;
 };
 
 }  // namespace rtcp
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTCP_PACKET_TARGET_BITRATE_H_