WIP for display item list backed by ListContainer

Source/platform/graphics/paint/CompositingDisplayItem.h

Index: Source/platform/graphics/paint/CompositingDisplayItem.h
diff --git a/Source/platform/graphics/paint/CompositingDisplayItem.h b/Source/platform/graphics/paint/CompositingDisplayItem.h
index 251ff30a6707922bf38fd31288cfaab83ae5a5b8..fb6ca353d3c3d90d8519fd57b476c8aefec48705 100644
--- a/Source/platform/graphics/paint/CompositingDisplayItem.h
+++ b/Source/platform/graphics/paint/CompositingDisplayItem.h
@@ -17,23 +17,17 @@
 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;
@@ -42,24 +36,15 @@ 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;