Shortcut decoder initialization when only using it for capability testing

app/streaming/session.h

@@ -83,6 +83,7 @@ private:
     bool chooseDecoder(StreamingPreferences::VideoDecoderSelection vds,
                        SDL_Window* window, int videoFormat, int width, int height,
                        int frameRate, bool enableVsync, bool enableFramePacing,
+                       bool testOnly,
                        IVideoDecoder*& chosenDecoder);
 
     static