Get VideoCapturer stats via VideoTrackSourceInterface in StatsCollector,

webrtc/media/base/mediachannel.h

Index: webrtc/media/base/mediachannel.h
diff --git a/webrtc/media/base/mediachannel.h b/webrtc/media/base/mediachannel.h
index 95355c9576a1afd117a4a5e4af43065b1a2cd654..09ac1fadaf9691f0c9c62953e112fbd2e4e79236 100644
--- a/webrtc/media/base/mediachannel.h
+++ b/webrtc/media/base/mediachannel.h
@@ -656,8 +656,6 @@ struct VideoSenderInfo : public MediaSenderInfo {
         firs_rcvd(0),
         plis_rcvd(0),
         nacks_rcvd(0),
-        input_frame_width(0),
-        input_frame_height(0),
         send_frame_width(0),
         send_frame_height(0),
         framerate_input(0),
@@ -676,8 +674,6 @@ struct VideoSenderInfo : public MediaSenderInfo {
   int firs_rcvd;
   int plis_rcvd;
   int nacks_rcvd;
-  int input_frame_width;
-  int input_frame_height;
   int send_frame_width;
   int send_frame_height;
   int framerate_input;