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

webrtc/modules/video_coding/generic_decoder.cc

Index: webrtc/modules/video_coding/generic_decoder.cc
diff --git a/webrtc/modules/video_coding/generic_decoder.cc b/webrtc/modules/video_coding/generic_decoder.cc
index 2121ab63067acdafe71e7f1cb7ceaf90c3b1196d..1dbb9b688fbf4f0cd451fde8e7c53f5bf8bd9dd7 100644
--- a/webrtc/modules/video_coding/generic_decoder.cc
+++ b/webrtc/modules/video_coding/generic_decoder.cc
@@ -87,6 +87,7 @@ void VCMDecodedFrameCallback::Decoded(VideoFrame& decodedImage,
   decodedImage.set_timestamp_us(
       frameInfo->renderTimeMs * rtc::kNumMicrosecsPerMillisec);
   decodedImage.set_rotation(frameInfo->rotation);
+  decodedImage.set_content_type(frameInfo->content_type);
   _receiveCallback->FrameToRender(decodedImage, qp);
 }
 
@@ -149,6 +150,7 @@ int32_t VCMGenericDecoder::Decode(const VCMEncodedFrame& frame, int64_t nowMs) {
     _frameInfos[_nextFrameInfoIdx].decodeStartTimeMs = nowMs;
     _frameInfos[_nextFrameInfoIdx].renderTimeMs = frame.RenderTimeMs();
     _frameInfos[_nextFrameInfoIdx].rotation = frame.rotation();
+    _frameInfos[_nextFrameInfoIdx].content_type = frame.contentType();
     _callback->Map(frame.TimeStamp(), &_frameInfos[_nextFrameInfoIdx]);
 
     _nextFrameInfoIdx = (_nextFrameInfoIdx + 1) % kDecoderFrameMemoryLength;