diff --git a/services/surfaceflinger/EventThread.h b/services/surfaceflinger/EventThread.h
index d1c4fcd..9ba179a 100644
--- a/services/surfaceflinger/EventThread.h
+++ b/services/surfaceflinger/EventThread.h
@@ -51,6 +51,7 @@
     virtual ~VSyncSource() {}
     virtual void setVSyncEnabled(bool enable) = 0;
     virtual void setCallback(const sp<Callback>& callback) = 0;
+    virtual void setPhaseOffset(nsecs_t phaseOffset) = 0;
 };
 
 class EventThread : public Thread, private VSyncSource::Callback {
@@ -99,6 +100,8 @@
     void dump(String8& result) const;
     void sendVsyncHintOff();
 
+    void setPhaseOffset(nsecs_t phaseOffset);
+
 private:
     virtual bool        threadLoop();
     virtual void        onFirstRef();