Style fixes in rtcp_packet/

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

 /*
  *  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.
  */
 
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/compound_packet.h"
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 namespace rtcp {
 
+CompoundPacket::CompoundPacket() = default;
+
+CompoundPacket::~CompoundPacket() = default;
+
 void CompoundPacket::Append(RtcpPacket* packet) {
   RTC_CHECK(packet);
   appended_packets_.push_back(packet);
 }
 
 bool CompoundPacket::Create(uint8_t* packet,
                             size_t* index,
                             size_t max_length,
                             RtcpPacket::PacketReadyCallback* callback) const {
   for (RtcpPacket* appended : appended_packets_) {
     if (!appended->Create(packet, index, max_length, callback))
       return false;
   }
   return true;
 }
 
 size_t CompoundPacket::BlockLength() const {
   size_t block_length = 0;
   for (RtcpPacket* appended : appended_packets_) {
     block_length += appended->BlockLength();
   }
   return block_length;
 }
 
 }  // namespace rtcp
 }  // namespace webrtc