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

webrtc/sdk/objc/Framework/Classes/objcvideotracksource.mm

 /*
  *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 46 matching lines @@
   }
 
   // Applying rotation is only supported for legacy reasons and performance is
   // not critical here.
   webrtc::VideoRotation rotation = static_cast<webrtc::VideoRotation>(frame.rotation);
   if (apply_rotation() && rotation != kVideoRotation_0) {
     buffer = I420Buffer::Rotate(buffer->NativeToI420Buffer(), rotation);
     rotation = kVideoRotation_0;
   }
 
-  OnFrame(webrtc::VideoFrame(buffer, rotation, translated_timestamp_us));
+  OnFrame(webrtc::VideoFrame(buffer, rotation, VideoContentType::kDefault,
+                             translated_timestamp_us));
 }
 
 }  // namespace webrtc