Make VCMEncodedFrameCallback const.

webrtc/modules/video_coding/main/source/video_receiver.cc

 /*
  *  Copyright (c) 2013 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 @@
       _packetRequestCallback(NULL),
       render_buffer_callback_(NULL),
       _decoder(NULL),
 #ifdef DEBUG_DECODER_BIT_STREAM
       _bitStreamBeforeDecoder(NULL),
 #endif
       _frameFromFile(),
       _scheduleKeyRequest(false),
       max_nack_list_size_(0),
       pre_decode_image_callback_(NULL),
-      _codecDataBase(NULL),
+      _codecDataBase(nullptr, nullptr),
       _receiveStatsTimer(1000, clock_),
       _retransmissionTimer(10, clock_),
       _keyRequestTimer(500, clock_) {
   assert(clock_);
 #ifdef DEBUG_DECODER_BIT_STREAM
   _bitStreamBeforeDecoder = fopen("decoderBitStream.bit", "wb");
 #endif
 }
 
 VideoReceiver::~VideoReceiver() {
@@ skipping 510 matching lines @@
 }
 
 void VideoReceiver::RegisterPreDecodeImageCallback(
     EncodedImageCallback* observer) {
   CriticalSectionScoped cs(_receiveCritSect);
   pre_decode_image_callback_ = observer;
 }
 
 }  // namespace vcm
 }  // namespace webrtc