Add encoder/decoder names to software H264.

BUG=
R=hbos@webrtc.org

Review URL: https://codereview.webrtc.org/2088513004 .

Cr-Commit-Position: refs/heads/master@{#13258}

webrtc/modules/video_coding/codecs/h264/h264_decoder_impl.cc

@@ -395,6 +395,10 @@ int32_t H264DecoderImpl::Decode(const EncodedImage& input_image,
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* H264DecoderImpl::ImplementationName() const {
+  return "FFmpeg";
+}
+
 bool H264DecoderImpl::IsInitialized() const {
   return av_context_ != nullptr;
 }

webrtc/modules/video_coding/codecs/h264/h264_decoder_impl.h

@@ -52,6 +52,8 @@ class H264DecoderImpl : public H264Decoder {
                  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

webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc

@@ -382,6 +382,10 @@ int32_t H264EncoderImpl::Encode(const VideoFrame& input_frame,
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* H264EncoderImpl::ImplementationName() const {
+  return "OpenH264";
+}
+
 bool H264EncoderImpl::IsInitialized() const {
   return openh264_encoder_ != nullptr;
 }

webrtc/modules/video_coding/codecs/h264/h264_encoder_impl.h

@@ -52,6 +52,8 @@ class H264EncoderImpl : public H264Encoder {
                  const CodecSpecificInfo* codec_specific_info,
                  const std::vector<FrameType>* frame_types) override;
 
+  const char* ImplementationName() const override;
+
   // Unsupported / Do nothing.
   int32_t SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
   int32_t SetPeriodicKeyFrames(bool enable) override;