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 0c5256ee016496e2fe7b923331a068f0bd5c31f6..5ba25592ad7fa645b5ed4f93dad05d67f4fef384 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]) {
@@ -1399,6 +1403,10 @@ 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.