diff --git a/services/surfaceflinger/ActivePictureTracker.h b/services/surfaceflinger/ActivePictureTracker.h
index 95a698b..cb319a5 100644
--- a/services/surfaceflinger/ActivePictureTracker.h
+++ b/services/surfaceflinger/ActivePictureTracker.h
@@ -19,6 +19,7 @@
 #include <vector>
 
 #include <android/gui/ActivePicture.h>
+#include <android/gui/IActivePictureListener.h>
 
 namespace android {
 
@@ -29,19 +30,26 @@
 // Keeps track of active pictures - layers that are undergoing picture processing.
 class ActivePictureTracker {
 public:
+    typedef std::vector<sp<gui::IActivePictureListener>> Listeners;
+
     // Called for each visible layer when SurfaceFlinger finishes composing.
     void onLayerComposed(const Layer& layer, const LayerFE& layerFE,
                          const CompositionResult& result);
 
     // Update internals and return whether the set of active pictures have changed.
-    bool updateAndHasChanged();
+    void updateAndNotifyListeners(const Listeners& activePictureListenersToAdd,
+                                  const Listeners& activePictureListenersToRemove);
 
     // The current set of active pictures.
     const std::vector<gui::ActivePicture>& getActivePictures() const;
 
 private:
+    Listeners updateListeners(const Listeners& listenersToAdd, const Listeners& listenersToRemove);
+    bool updateAndHasChanged();
+
     std::vector<gui::ActivePicture> mOldActivePictures;
     std::vector<gui::ActivePicture> mNewActivePictures;
+    Listeners mListeners;
 };
 
 } // namespace android