diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index 6b62c9d..b8f7680 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -103,8 +103,6 @@
             Rect visibleBounds() const;
             void drawRegion(const Region& reg) const;
 
-            void invalidate();
-
     virtual sp<LayerBaseClient> getLayerBaseClient() const { return 0; }
     virtual sp<Layer> getLayer() const { return 0; }
 
@@ -204,9 +202,16 @@
 
     /** called with the state lock when the surface is removed from the
      *  current list */
-    virtual void onRemoved() { };
+    virtual void onRemoved() { }
 
-    virtual void onLayerDisplayed() { };
+    /** called after page-flip
+     */
+    virtual void onLayerDisplayed() { }
+
+    /** called before composition.
+     * returns true if the layer has pending updates.
+     */
+    virtual bool onPreComposition() { return false; }
 
     /** always call base class first */
     virtual void dump(String8& result, char* scratch, size_t size) const;
@@ -275,10 +280,6 @@
     mutable     bool            mDebug;
 
 
-                // atomic
-    volatile    int32_t         mInvalidate;
-                
-
 public:
     // called from class SurfaceFlinger
     virtual ~LayerBase();