Make DisplayItemClient an interface

third_party/WebKit/Source/core/paint/PaintLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 138 matching lines @@
 //   concept.
 //
 // Its features need to be migrated to helper objects. This was started with the
 // introduction of satellite objects: PaintLayer*. Those helper objects then
 // need to be moved to the appropriate LayoutObject class, probably to a rare
 // data field to avoid growing all the LayoutObjects.
 //
 // A good example of this is PaintLayerScrollableArea, which can only happen
 // be instanciated for LayoutBoxes. With the current design, it's hard to know
 // that by reading the code.
-class CORE_EXPORT PaintLayer {
+class CORE_EXPORT PaintLayer : public DisplayItemClient {
     WTF_MAKE_NONCOPYABLE(PaintLayer);
 public:
     PaintLayer(LayoutBoxModelObject*, PaintLayerType);
     ~PaintLayer();
 
-    String debugName() const;
+    String debugName() const final;
 
     LayoutBoxModelObject* layoutObject() const { return m_layoutObject; }
     LayoutBox* layoutBox() const { return m_layoutObject && m_layoutObject->isBox() ? toLayoutBox(m_layoutObject) : 0; }
     PaintLayer* parent() const { return m_parent; }
     PaintLayer* previousSibling() const { return m_previous; }
     PaintLayer* nextSibling() const { return m_next; }
     PaintLayer* firstChild() const { return m_first; }
     PaintLayer* lastChild() const { return m_last; }
 
     // TODO(wangxianzhu): Find a better name for it. 'paintContainer' might be good but
@@ skipping 435 matching lines @@
     bool needsRepaint() const { return m_needsRepaint; }
     void setNeedsRepaint();
     void clearNeedsRepaintRecursively();
 
     IntSize previousScrollOffsetAccumulationForPainting() const { return m_previousScrollOffsetAccumulationForPainting; }
     void setPreviousScrollOffsetAccumulationForPainting(const IntSize& s) { m_previousScrollOffsetAccumulationForPainting = s; }
 
     ClipRects* previousPaintingClipRects() const { return m_previousPaintingClipRects.get(); }
     void setPreviousPaintingClipRects(ClipRects* clipRects) { m_previousPaintingClipRects = clipRects; }
 
-    // For subsequence display items.
-    DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
-
     PaintTiming* paintTiming();
 
 private:
     // Bounding box in the coordinates of this layer.
     LayoutRect logicalBoundingBox() const;
 
     bool hasOverflowControls() const;
 
     void dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();
 
@@ skipping 182 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::PaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h