fix dumpsys Layer name when using multiple displays

Bug: 7288401
Change-Id: I14beeef58fac5270cef3b611e18c163060efe6c3
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 5bb3703..6d36719 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -130,6 +130,10 @@
     // TODO: this should be made accessible only to MessageQueue
     void onMessageReceived(int32_t what);
 
+    // for debugging only
+    // TODO: this should be made accessible only to HWComposer
+    const Vector< sp<LayerBase> >& getLayerSortedByZForHwcDisplay(int disp);
+
 private:
     friend class Client;
     friend class DisplayEventConnection;