Expose codec implementation names in stats.

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_decoder.h

 /*
  *  Copyright (c) 2015 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 @@
              const RTPFragmentationHeader* fragmentation,
              const CodecSpecificInfo* codec_specific_info,
              int64_t render_time_ms) override;
 
   int RegisterDecodeCompleteCallback(DecodedImageCallback* callback) override;
 
   int Release() override;
 
   int Reset() override;
 
+  const char* ImplementationName() const override;
+
  private:
   int ResetDecompressionSession();
   void ConfigureDecompressionSession();
   void DestroyDecompressionSession();
   void SetVideoFormat(CMVideoFormatDescriptionRef video_format);
 
   DecodedImageCallback* callback_;
   CMVideoFormatDescriptionRef video_format_;
   VTDecompressionSessionRef decompression_session_;
 };  // H264VideoToolboxDecoder
 
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_H264_H264_VIDEO_TOOLBOX_DECODER_H_