Add totalDecodeTime to RTCInboundRTPStreamStats

Pull request to WebRTC stats specification:
https://github.com/w3c/webrtc-stats/pull/450

Bug: webrtc:10775
Change-Id: Id032cb324724329fee284ebc84595b9c39208ab8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144035
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28440}
diff --git a/call/video_receive_stream.h b/call/video_receive_stream.h
index 8bd9982..4bc9b28 100644
--- a/call/video_receive_stream.h
+++ b/call/video_receive_stream.h
@@ -85,6 +85,8 @@
     int render_delay_ms = 10;
     int64_t interframe_delay_max_ms = -1;
     uint32_t frames_decoded = 0;
+    // https://w3c.github.io/webrtc-stats/#dom-rtcinboundrtpstreamstats-totaldecodetime
+    uint64_t total_decode_time_ms = 0;
     int64_t first_frame_received_to_decoded_ms = -1;
     absl::optional<uint64_t> qp_sum;