Implement googContentType GetStats metric reported on receive side.

webrtc/video/receive_statistics_proxy.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 483 matching lines @@
   // us from ever correctly displaying frame rate of 0.
   int64_t now_ms = clock_->TimeInMilliseconds();
   UpdateFramerate(now_ms);
   stats_.render_frame_rate = renders_fps_estimator_.Rate(now_ms).value_or(0);
   stats_.decode_frame_rate = decode_fps_estimator_.Rate(now_ms).value_or(0);
   stats_.total_bitrate_bps =
       static_cast<int>(total_byte_tracker_.ComputeRate() * 8);
   stats_.interframe_delay_max_ms =
       interframe_delay_max_moving_.Max(now_ms).value_or(-1);
   stats_.timing_frame_info = timing_frame_info_counter_.Max(now_ms);
+  stats_.content_type = last_content_type_;
   return stats_;
 }
 
 void ReceiveStatisticsProxy::OnIncomingPayloadType(int payload_type) {
   rtc::CritScope lock(&crit_);
   stats_.current_payload_type = payload_type;
 }
 
 void ReceiveStatisticsProxy::OnDecoderImplementationName(
     const char* implementation_name) {
@@ skipping 280 matching lines @@
   flow_duration_ms += other.flow_duration_ms;
   total_media_bytes += other.total_media_bytes;
   received_height.Add(other.received_height);
   received_width.Add(other.received_width);
   qp_counter.Add(other.qp_counter);
   frame_counts.key_frames += other.frame_counts.key_frames;
   frame_counts.delta_frames += other.frame_counts.delta_frames;
 }
 
 }  // namespace webrtc