Implement scoped_const_refptr template.

webrtc/modules/rtp_rtcp/source/forward_error_correction.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.
  */
 
@@ skipping 25 matching lines @@
   // TODO(holmer): As a next step all these struct-like packet classes should be
   // refactored into proper classes, and their members should be made private.
   // This will require parts of the functionality in forward_error_correction.cc
   // and receiver_fec.cc to be refactored into the packet classes.
   class Packet {
    public:
     Packet() : length(0), data(), ref_count_(0) {}
     virtual ~Packet() {}
 
     // Add a reference.
-    virtual int32_t AddRef();
+    virtual int32_t AddRef() const;
 
     // Release a reference. Will delete the object if the reference count
     // reaches zero.
-    virtual int32_t Release();
+    virtual int32_t Release() const;
 
     size_t length;               // Length of packet in bytes.
     uint8_t data[IP_PACKET_SIZE];  // Packet data.
 
    private:
-    int32_t ref_count_;  // Counts the number of references to a packet.
+    mutable int32_t ref_count_;  // Counts the number of references to a packet.
   };
 
   // TODO(holmer): Refactor into a proper class.
   class SortablePacket {
    public:
     // True if first is <= than second.
     static bool LessThan(const SortablePacket* first,
                          const SortablePacket* second);
 
     uint16_t seq_num;
@@ skipping 235 matching lines @@
   static void DiscardFECPacket(FecPacket* fec_packet);
   static void DiscardOldPackets(RecoveredPacketList* recovered_packet_list);
   static uint16_t ParseSequenceNumber(uint8_t* packet);
 
   std::vector<Packet> generated_fec_packets_;
   FecPacketList fec_packet_list_;
   bool fec_packet_received_;
 };
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_FORWARD_ERROR_CORRECTION_H_