Expose codec implementation names in stats.

webrtc/modules/video_coding/codecs/h264/h264_video_toolbox_encoder.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 30 matching lines @@
              const std::vector<FrameType>* frame_types) override;
 
   int RegisterEncodeCompleteCallback(EncodedImageCallback* callback) override;
 
   int SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
 
   int SetRates(uint32_t new_bitrate_kbit, uint32_t frame_rate) override;
 
   int Release() override;
 
+  const char* ImplementationName() const override;
+
  private:
   int ResetCompressionSession();
   void ConfigureCompressionSession();
   void DestroyCompressionSession();
 
   webrtc::EncodedImageCallback* callback_;
   VTCompressionSessionRef compression_session_;
   int32_t bitrate_;  // Bitrate in bits per second.
   int32_t width_;
   int32_t height_;
 };  // H264VideoToolboxEncoder
 
 }  // namespace webrtc
 
 #endif  // defined(WEBRTC_VIDEO_TOOLBOX_SUPPORTED)
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_H264_H264_VIDEO_TOOLBOX_ENCODER_H_