Refactoring: Hide VideoCodec.codecSpecific as "private"

webrtc/modules/video_coding/video_sender.cc

Index: webrtc/modules/video_coding/video_sender.cc
diff --git a/webrtc/modules/video_coding/video_sender.cc b/webrtc/modules/video_coding/video_sender.cc
index f52b1c56e7b550127507610f1696becdf73de699..f44180609a7fd7116a283159beef38648b530bdd 100644
--- a/webrtc/modules/video_coding/video_sender.cc
+++ b/webrtc/modules/video_coding/video_sender.cc
@@ -111,9 +111,9 @@ int32_t VideoSender::RegisterSendCodec(const VideoCodec* sendCodec,
 
   int numLayers;
   if (sendCodec->codecType == kVideoCodecVP8) {
-    numLayers = sendCodec->codecSpecific.VP8.numberOfTemporalLayers;
+    numLayers = sendCodec->VP8().numberOfTemporalLayers;
   } else if (sendCodec->codecType == kVideoCodecVP9) {
-    numLayers = sendCodec->codecSpecific.VP9.numberOfTemporalLayers;
+    numLayers = sendCodec->VP9().numberOfTemporalLayers;
   } else {
     numLayers = 1;
   }