Expose codec implementation names in stats.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc

Index: webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
index 3c7cc4ddd373e0afc806ebb73a0fe18af6e07b2a..8a3c456056c0d2d6448f92cf4bcdea82ad3fdbc6 100644
--- a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.cc
@@ -301,6 +301,10 @@ int VP8EncoderImpl::SetRates(uint32_t new_bitrate_kbit,
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* VP8EncoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 void VP8EncoderImpl::SetStreamState(bool send_stream,
                                             int stream_idx) {
   if (send_stream && !send_stream_[stream_idx]) {
@@ -1400,6 +1404,10 @@ int VP8DecoderImpl::Release() {
   return WEBRTC_VIDEO_CODEC_OK;
 }
 
+const char* VP8DecoderImpl::ImplementationName() const {
+  return "libvpx";
+}
+
 int VP8DecoderImpl::CopyReference(VP8DecoderImpl* copy) {
   // The type of frame to copy should be set in ref_frame_->frame_type
   // before the call to this function.