Reland of Add content type information to encoded images and corresponding rtp extension header

webrtc/video/rtp_stream_receiver.cc

Index: webrtc/video/rtp_stream_receiver.cc
diff --git a/webrtc/video/rtp_stream_receiver.cc b/webrtc/video/rtp_stream_receiver.cc
index 90dd0da0e1cda44c4e130aa6ef55fef9303f7b9b..00f1c46efa3995ea837165b61db08fb9b14af665 100644
--- a/webrtc/video/rtp_stream_receiver.cc
+++ b/webrtc/video/rtp_stream_receiver.cc
@@ -502,6 +502,10 @@
   if (header.extension.hasVideoRotation) {
     rtp_header.type.Video.rotation = header.extension.videoRotation;
   }
+  rtp_header.type.Video.content_type = VideoContentType::UNSPECIFIED;
+  if (header.extension.hasVideoContentType) {
+    rtp_header.type.Video.content_type = header.extension.videoContentType;
+  }
   rtp_header.type.Video.playout_delay = header.extension.playout_delay;
 
   OnReceivedPayloadData(nullptr, 0, &rtp_header);