Add encoder/decoder names to software H264.

webrtc/modules/video_coding/codecs/h264/h264_decoder_impl.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 34 matching lines @@
   int32_t RegisterDecodeCompleteCallback(
       DecodedImageCallback* callback) override;
 
   // |missing_frames|, |fragmentation| and |render_time_ms| are ignored.
   int32_t Decode(const EncodedImage& input_image,
                  bool /*missing_frames*/,
                  const RTPFragmentationHeader* /*fragmentation*/,
                  const CodecSpecificInfo* codec_specific_info = nullptr,
                  int64_t render_time_ms = -1) override;
 
+  const char* ImplementationName() const override;
+
  private:
   // Called by FFmpeg when it needs a frame buffer to store decoded frames in.
   // The |VideoFrame| returned by FFmpeg at |Decode| originate from here. Their
   // buffers are reference counted and freed by FFmpeg using |AVFreeBuffer2|.
   static int AVGetBuffer2(
       AVCodecContext* context, AVFrame* av_frame, int flags);
   // Called by FFmpeg when it is done with a video frame, see |AVGetBuffer2|.
   static void AVFreeBuffer2(void* opaque, uint8_t* data);
 
   bool IsInitialized() const;
 
   // Reports statistics with histograms.
   void ReportInit();
   void ReportError();
 
   I420BufferPool pool_;
   std::unique_ptr<AVCodecContext, AVCodecContextDeleter> av_context_;
   std::unique_ptr<AVFrame, AVFrameDeleter> av_frame_;
 
   DecodedImageCallback* decoded_image_callback_;
 
   bool has_reported_init_;
   bool has_reported_error_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_H264_H264_DECODER_IMPL_H_