Update Packet::GetHeader() to copy playout_delay

webrtc/modules/rtp_rtcp/source/rtp_packet.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_packet.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
index 7a7c45d38302ca893324003fbd603ee2b34eb3ae..6fe226660120a4e7693888b137d48492e1e1a701 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
@@ -169,6 +169,7 @@ void Packet::GetHeader(RTPHeader* header) const {
       &header->extension.voiceActivity, &header->extension.audioLevel);
   header->extension.hasVideoRotation =
       GetExtension<VideoOrientation>(&header->extension.videoRotation);
+  GetExtension<PlayoutDelayLimits>(&header->extension.playout_delay);
 }
 
 size_t Packet::headers_size() const {