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

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

Index: webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.cc
index 913264223fa08f4dc12cad46b278409d67f5cf46..e4cb7c9108cb2e3e848e13e67b7f0c243a7a662b 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/target_bitrate.cc
@@ -65,15 +65,7 @@ TargetBitrate::BitrateItem::BitrateItem(uint8_t spatial_layer,
 TargetBitrate::TargetBitrate() {}
 TargetBitrate::~TargetBitrate() {}
 
-bool TargetBitrate::Parse(const uint8_t* block, uint16_t block_length) {
-  if (block_length < 1) {
-    LOG(LS_WARNING)
-        << "Cannot parse TargetBitrate RTCP packet: Too little payload data ("
-        << kTargetBitrateHeaderSizeBytes << " bytes needed, got "
-        << block_length * 4 << ").";
-    return false;
-  }
-
+void TargetBitrate::Parse(const uint8_t* block, uint16_t block_length) {
   // Validate block header (should already have been parsed and checked).
   RTC_DCHECK_EQ(block[0], kBlockType);
   RTC_DCHECK_EQ(block_length, ByteReader<uint16_t>::ReadBigEndian(&block[2]));
@@ -91,8 +83,6 @@ bool TargetBitrate::Parse(const uint8_t* block, uint16_t block_length) {
     index += kBitrateItemSizeBytes;
     AddTargetBitrate((layers >> 4) & 0x0F, layers & 0x0F, bitrate_kbps);
   }
-
-  return true;
 }
 
 void TargetBitrate::AddTargetBitrate(uint8_t spatial_layer,