hack up frame latency measurement

Change-Id: I6d9a466a23285304f0e229a5649815636ab5d6af
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 2b9471b..9686259 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -78,6 +78,8 @@
     // LayerBaseClient interface
     virtual wp<IBinder> getSurfaceTextureBinder() const;
 
+    virtual void onLayerDisplayed();
+
     // only for debugging
     inline const sp<GraphicBuffer>& getActiveBuffer() const { return mActiveBuffer; }
 
@@ -110,6 +112,9 @@
     uint32_t mCurrentTransform;
     uint32_t mCurrentScalingMode;
     bool mCurrentOpacity;
+    bool mFrameLatencyNeeded;
+    int mFrameLatencyOffset;
+    int64_t mFrameLatencies[128];
 
     // constants
     PixelFormat mFormat;