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

webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc b/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
index d6c5e5c29b6ac4667f80681c0df5322d645747a1..debe836d8d70e853a36f8d32b9b59ad99ce9426f 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_receiver_video.cc
@@ -90,11 +90,17 @@
   rtp_header->frameType = parsed_payload.frame_type;
   rtp_header->type = parsed_payload.type;
   rtp_header->type.Video.rotation = kVideoRotation_0;
+  rtp_header->type.Video.content_type = VideoContentType::UNSPECIFIED;
 
   // Retrieve the video rotation information.
   if (rtp_header->header.extension.hasVideoRotation) {
     rtp_header->type.Video.rotation =
         rtp_header->header.extension.videoRotation;
+  }
+
+  if (rtp_header->header.extension.hasVideoContentType) {
+    rtp_header->type.Video.content_type =
+        rtp_header->header.extension.videoContentType;
   }
 
   rtp_header->type.Video.playout_delay =