Refactor to simplify how layerType is stored on PaintLayers.

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 359 matching lines @@
     }
     // Move all of the kids from |startChild| up to but excluding |endChild|. 0 can be passed as the |endChild| to denote
     // that all the kids from |startChild| onwards should be moved.
     void moveChildrenTo(LayoutBoxModelObject* toBoxModelObject, LayoutObject* startChild, LayoutObject* endChild, bool fullRemoveInsert = false)
     {
         moveChildrenTo(toBoxModelObject, startChild, endChild, 0, fullRemoveInsert);
     }
     virtual void moveChildrenTo(LayoutBoxModelObject* toBoxModelObject, LayoutObject* startChild, LayoutObject* endChild, LayoutObject* beforeChild, bool fullRemoveInsert = false);
 
 private:
-    void createLayer(PaintLayerType);
+    void createLayer();
 
     LayoutUnit computedCSSPadding(const Length&) const;
     bool isBoxModelObject() const final { return true; }
 
     LayoutBoxModelObjectRareData& ensureRareData()
     {
         if (!m_rareData)
             m_rareData = adoptPtr(new LayoutBoxModelObjectRareData());
         return *m_rareData.get();
     }
 
     // The PaintLayer associated with this object.
     // |m_layer| can be nullptr depending on the return value of layerTypeRequired().
     OwnPtr<PaintLayer> m_layer;
 
     OwnPtr<LayoutBoxModelObjectRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBoxModelObject, isBoxModelObject());
 
 } // namespace blink
 
 #endif // LayoutBoxModelObject_h