Revert "Layer: Use raw pointers for Current/Drawing parent"

This reverts commit cbdb79a195e6c690e16948a7e7c3abbd36414b17.

Bug: 203175614
Bug: 203559094
Change-Id: I5432ad46bfbbe5a009e3fb72ae7ac129263260ce
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index db3b572..7072439 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -289,7 +289,7 @@
     }
 
     static void setLayerDrawingParent(const sp<Layer>& layer, const sp<Layer>& drawingParent) {
-        layer->mDrawingParent = drawingParent.get();
+        layer->mDrawingParent = drawingParent;
     }
 
     /* ------------------------------------------------------------------------