WIP for display item list backed by ListContainer

Source/platform/graphics/paint/CompositingDisplayItem.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CompositingDisplayItem_h
 #define CompositingDisplayItem_h
 
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/GraphicsTypes.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "public/platform/WebBlendMode.h"
 #include "wtf/PassOwnPtr.h"
 #ifndef NDEBUG
 #include "wtf/text/WTFString.h"
 #endif
 
 namespace blink {
 
 class PLATFORM_EXPORT BeginCompositingDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(BeginCompositingDisplayItem);
 public:
-    static PassOwnPtr<BeginCompositingDisplayItem> create(const DisplayItemClientWrapper& client, const SkXfermode::Mode xferMode, const float opacity, const FloatRect* bounds = nullptr, ColorFilter colorFilter = ColorFilterNone)
+    void setNew(SkXfermode::Mode xferMode, float opacity, FloatRect* bounds = nullptr, ColorFilter colorFilter = ColorFilterNone)
     {
-        return adoptPtr(new BeginCompositingDisplayItem(client, xferMode, opacity, bounds, colorFilter));
+        m_xferMode = xferMode;
+        m_opacity = opacity;
+        m_hasBounds = !!bounds;
+        if (bounds)
+            m_bounds = FloatRect(*bounds);
+        m_colorFilter = colorFilter;
+
     }
 
-    BeginCompositingDisplayItem(const DisplayItemClientWrapper& client, const SkXfermode::Mode xferMode, const float opacity, const FloatRect* bounds, ColorFilter colorFilter = ColorFilterNone)
-        : PairedBeginDisplayItem(client, BeginCompositing)
-        , m_xferMode(xferMode)
-        , m_opacity(opacity)
-        , m_hasBounds(bounds)
-        , m_colorFilter(colorFilter)
-        {
-            if (bounds)
-                m_bounds = FloatRect(*bounds);
-        }
-
     virtual void replay(GraphicsContext&) override;
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;
 
 private:
 #ifndef NDEBUG
     virtual void dumpPropertiesAsDebugString(WTF::StringBuilder&) const override;
 #endif
-    const SkXfermode::Mode m_xferMode;
-    const float m_opacity;
+    SkXfermode::Mode m_xferMode;
+    float m_opacity;
     bool m_hasBounds;
     FloatRect m_bounds;
     ColorFilter m_colorFilter;
 };
 
 class PLATFORM_EXPORT EndCompositingDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndCompositingDisplayItem);
 public:
-    static PassOwnPtr<EndCompositingDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new EndCompositingDisplayItem(client));
-    }
-
-    EndCompositingDisplayItem(const DisplayItemClientWrapper& client)
-        : PairedEndDisplayItem(client, EndCompositing) { }
-
     virtual void replay(GraphicsContext&) override;
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;
 
 private:
 #if ENABLE(ASSERT)
     virtual bool isEndAndPairedWith(DisplayItem::Type otherType) const override final { return otherType == BeginCompositing; }
 #endif
 };
 
 } // namespace blink
 
 #endif // CompositingDisplayItem_h