WIP for display item list backed by ListContainer

Source/platform/graphics/paint/FloatClipDisplayItem.h

Index: Source/platform/graphics/paint/FloatClipDisplayItem.h
diff --git a/Source/platform/graphics/paint/FloatClipDisplayItem.h b/Source/platform/graphics/paint/FloatClipDisplayItem.h
index 9aa0a866f4030b20d76e161964d14aba49b3ba0a..681696aec141ea21564d50c7bb7e962abfd18348 100644
--- a/Source/platform/graphics/paint/FloatClipDisplayItem.h
+++ b/Source/platform/graphics/paint/FloatClipDisplayItem.h
@@ -15,18 +15,11 @@ namespace blink {
 class RoundedRect;
 
 class PLATFORM_EXPORT FloatClipDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(FloatClipDisplayItem);
 public:
-    static PassOwnPtr<FloatClipDisplayItem> create(const DisplayItemClientWrapper& client, Type type, const FloatRect& clipRect)
+    void setNew(FloatRect& clipRect)
     {
-        return adoptPtr(new FloatClipDisplayItem(client, type, clipRect));
-    }
-
-    FloatClipDisplayItem(const DisplayItemClientWrapper& client, Type type, const FloatRect& clipRect)
-        : PairedBeginDisplayItem(client, type)
-        , m_clipRect(clipRect)
-    {
-        ASSERT(isFloatClipType(type));
+        m_clipRect = clipRect;
+        ASSERT(isFloatClipType(type()));
     }
 
     virtual void replay(GraphicsContext&) override;
@@ -41,19 +34,7 @@ private:
 };
 
 class PLATFORM_EXPORT EndFloatClipDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndFloatClipDisplayItem);
 public:
-    static PassOwnPtr<EndFloatClipDisplayItem> create(const DisplayItemClientWrapper& client, Type type)
-    {
-        return adoptPtr(new EndFloatClipDisplayItem(client, type));
-    }
-
-    EndFloatClipDisplayItem(const DisplayItemClientWrapper& client, Type type)
-        : PairedEndDisplayItem(client, type)
-    {
-        ASSERT(isEndFloatClipType(type));
-    }
-
     virtual void replay(GraphicsContext&) override;
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;