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

webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h

Index: webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h
diff --git a/webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h b/webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h
index 8a53c1d31a19593fb7b76fede6f1201d72704857..21b154f8d18ae7f6e982ae5028e8cc436de9ba29 100644
--- a/webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h
+++ b/webrtc/modules/video_coding/include/mock/mock_vcm_callbacks.h
@@ -33,7 +33,8 @@
   MockVCMReceiveCallback() {}
   virtual ~MockVCMReceiveCallback() {}
 
-  MOCK_METHOD2(FrameToRender, int32_t(VideoFrame&, rtc::Optional<uint8_t>));
+  MOCK_METHOD3(FrameToRender,
+               int32_t(VideoFrame&, rtc::Optional<uint8_t>, VideoContentType));
   MOCK_METHOD1(ReceivedDecodedReferenceFrame, int32_t(const uint64_t));
   MOCK_METHOD1(OnIncomingPayloadType, void(int));
   MOCK_METHOD1(OnDecoderImplementationName, void(const char*));