Fix BWE bug where audio has timestamps in us.

webrtc/video/audio_receive_stream.cc

Index: webrtc/video/audio_receive_stream.cc
diff --git a/webrtc/video/audio_receive_stream.cc b/webrtc/video/audio_receive_stream.cc
index b8da1bb6c35da0bd984b9c0a74f6f7b04180bbc4..a1cf2ca33ef07e8357aa23898e28d45f39fca3dc 100644
--- a/webrtc/video/audio_receive_stream.cc
+++ b/webrtc/video/audio_receive_stream.cc
@@ -102,7 +102,7 @@ bool AudioReceiveStream::DeliverRtp(const uint8_t* packet,
       header.extension.hasAbsoluteSendTime) {
     int64_t arrival_time_ms = TickTime::MillisecondTimestamp();
     if (packet_time.timestamp >= 0)
-      arrival_time_ms = packet_time.timestamp;
+      arrival_time_ms = (packet_time.timestamp + 500) / 1000;
     size_t payload_size = length - header.headerLength;
     remote_bitrate_estimator_->IncomingPacket(arrival_time_ms, payload_size,
                                               header, false);