Render timing

apps/RenderCadenceCompositor/frames/SystemFrameExchange.h

@@ -22,6 +22,10 @@ public:
 	bool ConsumeCompletedForSchedule(SystemFrame& frame);
 	bool ReleaseScheduledByBytes(void* bytes);
 	bool WaitForCompletedDepth(std::size_t targetDepth, std::chrono::milliseconds timeout);
+	bool WaitForStableCompletedDepth(
+		std::size_t targetDepth,
+		std::chrono::milliseconds stableDuration,
+		std::chrono::milliseconds timeout);
 	void Clear();
 
 	SystemFrameExchangeMetrics Metrics() const;