diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 6f07964..b4db933 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -176,6 +176,10 @@
     // set-top boxes after a hotplug reconnect.
     DisplayModePtr getMode(DisplayModeId) const;
 
+    void onVsync(nsecs_t timestamp);
+    nsecs_t getVsyncPeriodFromHWC() const;
+    nsecs_t getRefreshTimestamp() const;
+
     // release HWC resources (if any) for removable displays
     void disconnect();
 
@@ -207,6 +211,8 @@
     DisplayModeId mActiveModeId;
     const DisplayModes mSupportedModes;
 
+    std::atomic<nsecs_t> mLastHwVsync = 0;
+
     // TODO(b/74619554): Remove special cases for primary display.
     const bool mIsPrimary;