SF: add a backdoor to introduce a janky frame to HWC

Bug: 346503493
Test: adb shell service call SurfaceFlinger 1046 i32 3Test: adb root && adb shell service call SurfaceFlinger 1046 i32 3
Flag: EXEMPT bugfix
Change-Id: Ic4a837ef06aca40a24db9c1121e19e3e1a1e0d80
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 8340880..61c68a9 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -337,6 +337,8 @@
     // recovery should begin.
     void addBufferStuffedUids(BufferStuffingMap bufferStuffedUids);
 
+    void setDebugPresentDelay(TimePoint delay) { mDebugPresentDelay = delay; }
+
 private:
     friend class TestableScheduler;
 
@@ -602,6 +604,8 @@
 
     FrameRateOverrideMappings mFrameRateOverrideMappings;
     SmallAreaDetectionAllowMappings mSmallAreaDetectionAllowMappings;
+
+    std::atomic<std::optional<TimePoint>> mDebugPresentDelay;
 };
 
 } // namespace scheduler