[Mirror Layers] Added clone function to layers (1/4)

Added a cloning function to each layer in preparation for mirroring

Test: Nothing to test yet since no calls
Bug: 131622422
Change-Id: Iba0692b75c4d99841de48f40ed55b3dbccf2b9b9
diff --git a/services/surfaceflinger/BufferStateLayer.h b/services/surfaceflinger/BufferStateLayer.h
index 52063fc..e951ccf 100644
--- a/services/surfaceflinger/BufferStateLayer.h
+++ b/services/surfaceflinger/BufferStateLayer.h
@@ -124,13 +124,13 @@
     status_t updateFrameNumber(nsecs_t latchTime) override;
 
     void latchPerFrameState(compositionengine::LayerFECompositionState&) const override;
+    sp<Layer> createClone() override;
 
     // Crop that applies to the buffer
     Rect computeCrop(const State& s);
 
 private:
     friend class SlotGenerationTest;
-    void onFirstRef() override;
     bool willPresentCurrentTransaction() const;
 
     static const std::array<float, 16> IDENTITY_MATRIX;