Delete unused members of MediaReceiverInfo and MediaSenderInfo

The deleted members are bytes_sent, bytes_received,
and (receive-side) fraction_lost.

Followup to https://webrtc-review.googlesource.com/c/src/+/143178.

Bug: webrtc:10744, webrtc:10525
Change-Id: Ibd8b15619c78b82a9dc18abddb6e1687fae60c88
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/143902
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29566}
diff --git a/media/base/media_channel.h b/media/base/media_channel.h
index c20e039..3450c443 100644
--- a/media/base/media_channel.h
+++ b/media/base/media_channel.h
@@ -393,9 +393,6 @@
       return 0;
     }
   }
-  // TODO(bugs.webrtc.org/10525): Unused, delete as soon as downstream code is
-  // updated.
-  int64_t bytes_sent;
   // https://w3c.github.io/webrtc-stats/#dom-rtcsentrtpstreamstats-bytessent
   int64_t payload_bytes_sent = 0;
   // https://w3c.github.io/webrtc-stats/#dom-rtcoutboundrtpstreamstats-headerbytessent
@@ -453,18 +450,12 @@
     }
   }
 
-  // TODO(bugs.webrtc.org/10525): Unused, delete as soon as downstream code is
-  // updated.
-  int64_t bytes_rcvd;
   // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-bytesreceived
   int64_t payload_bytes_rcvd = 0;
   // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-headerbytesreceived
   int64_t header_and_padding_bytes_rcvd = 0;
   int packets_rcvd = 0;
   int packets_lost = 0;
-  // TODO(bugs.webrtc.org/10679): Unused, delete as soon as downstream code is
-  // updated.
-  float fraction_lost = 0.0f;
   // The timestamp at which the last packet was received, i.e. the time of the
   // local clock when it was received - not the RTP timestamp of that packet.
   // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-lastpacketreceivedtimestamp