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

webrtc/modules/video_coding/video_sender.cc

Index: webrtc/modules/video_coding/video_sender.cc
diff --git a/webrtc/modules/video_coding/video_sender.cc b/webrtc/modules/video_coding/video_sender.cc
index 0b54d13b2901e1bfc7faf03e309a64f4d28a3dd8..d78ca50005d0dba0983b393ee3ffde6b40ccbbc4 100644
--- a/webrtc/modules/video_coding/video_sender.cc
+++ b/webrtc/modules/video_coding/video_sender.cc
@@ -337,10 +337,10 @@ int32_t VideoSender::AddVideoFrame(const VideoFrame& videoFrame,
       LOG(LS_ERROR) << "Frame conversion failed, dropping frame.";
       return VCM_PARAMETER_ERROR;
     }
-    converted_frame = VideoFrame(converted_buffer,
-                                 converted_frame.timestamp(),
-                                 converted_frame.render_time_ms(),
-                                 converted_frame.rotation());
+    converted_frame =
+        VideoFrame(converted_buffer, converted_frame.timestamp(),
+                   converted_frame.render_time_ms(), converted_frame.rotation(),
+                   converted_frame.content_type());
   }
   int32_t ret =
       _encoder->Encode(converted_frame, codecSpecificInfo, next_frame_types);