Wait for the VDPAU output surface to be idle in waitToRender()

app/streaming/video/ffmpeg-renderers/vdpau.h

@@ -16,6 +16,7 @@ public:
     virtual bool initialize(PDECODER_PARAMETERS params) override;
     virtual bool prepareDecoderContext(AVCodecContext* context, AVDictionary** options) override;
     virtual void notifyOverlayUpdated(Overlay::OverlayType type) override;
+    virtual void waitToRender() override;
     virtual void renderFrame(AVFrame* frame) override;
     virtual bool needsTestFrame() override;
     virtual int getDecoderColorspace() override;