CompositionEngine: fix memory leak in unit tests

LayerFE implements RefBase, and instantiating it on stack
causes a memory leak of the shared state.

Bug: 198190384
Test: libcompositionengine_test
Change-Id: If0f847bdf93359b206f7ce77ded9a8d5feb4e31c
diff --git a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
index 325361b..de9de01 100644
--- a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
@@ -203,9 +203,9 @@
  */
 
 struct CompositionTestPreComposition : public CompositionEngineTest {
-    sp<StrictMock<mock::LayerFE>> mLayer1FE{new StrictMock<mock::LayerFE>()};
-    sp<StrictMock<mock::LayerFE>> mLayer2FE{new StrictMock<mock::LayerFE>()};
-    sp<StrictMock<mock::LayerFE>> mLayer3FE{new StrictMock<mock::LayerFE>()};
+    sp<StrictMock<mock::LayerFE>> mLayer1FE = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> mLayer2FE = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> mLayer3FE = sp<StrictMock<mock::LayerFE>>::make();
 };
 
 TEST_F(CompositionTestPreComposition, preCompositionSetsFrameTimestamp) {