SF: refactor renderScreenImpl to use CompositionEngine

Bug: 238643986
Test: presubmits
Test: go/wm-smoke

Change-Id: I6dbbcd5ce5070ec1d801dca55b5bb89fafe839cb
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index a3c4e59..9585fa9 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -323,6 +323,7 @@
     ui::Dataspace getRequestedDataSpace() const;
 
     virtual sp<LayerFE> getCompositionEngineLayerFE() const;
+    virtual sp<LayerFE> copyCompositionEngineLayerFE() const;
 
     const LayerSnapshot* getLayerSnapshot() const;
     LayerSnapshot* editLayerSnapshot();