diff --git a/services/surfaceflinger/DispSync.h b/services/surfaceflinger/DispSync.h
index 2763e59..5b7083d 100644
--- a/services/surfaceflinger/DispSync.h
+++ b/services/surfaceflinger/DispSync.h
@@ -182,6 +182,10 @@
 
     // mMutex is used to protect access to all member variables.
     mutable Mutex mMutex;
+
+    // This is the offset from the present fence timestamps to the corresponding
+    // vsync event.
+    int64_t mPresentTimeOffset;
 };
 
 }