WIP for display item list backed by ListContainer

Source/platform/graphics/paint/ClipDisplayItem.h

Index: Source/platform/graphics/paint/ClipDisplayItem.h
diff --git a/Source/platform/graphics/paint/ClipDisplayItem.h b/Source/platform/graphics/paint/ClipDisplayItem.h
index 65c2754a49998a4ca2ec0a0e53851cdc10ecee6a..ccc14f82213e15aa1e077dd5d5d9a249bb76147c 100644
--- a/Source/platform/graphics/paint/ClipDisplayItem.h
+++ b/Source/platform/graphics/paint/ClipDisplayItem.h
@@ -16,19 +16,12 @@
 namespace blink {
 
 class PLATFORM_EXPORT ClipDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(ClipDisplayItem);
 public:
-    static PassOwnPtr<ClipDisplayItem> create(const DisplayItemClientWrapper& client, Type type, const IntRect& clipRect, PassOwnPtr<Vector<FloatRoundedRect>> roundedRectClips = nullptr)
+    void setNew(IntRect& clipRect, PassOwnPtr<Vector<FloatRoundedRect>> roundedRectClips = nullptr)
     {
-        return adoptPtr(new ClipDisplayItem(client, type, clipRect, roundedRectClips));
-    }
-
-    ClipDisplayItem(const DisplayItemClientWrapper& client, Type type, const IntRect& clipRect, PassOwnPtr<Vector<FloatRoundedRect>> roundedRectClips = nullptr)
-        : PairedBeginDisplayItem(client, type)
-        , m_clipRect(clipRect)
-        , m_roundedRectClips(roundedRectClips)
-    {
-        ASSERT(isClipType(type));
+        m_clipRect = clipRect;
+        m_roundedRectClips = roundedRectClips;
+        ASSERT(isClipType(type()));
     }
 
     virtual void replay(GraphicsContext&) override;
@@ -43,19 +36,7 @@ private:
 };
 
 class PLATFORM_EXPORT EndClipDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndClipDisplayItem);
 public:
-    static PassOwnPtr<EndClipDisplayItem> create(const DisplayItemClientWrapper& client, Type type)
-    {
-        return adoptPtr(new EndClipDisplayItem(client, type));
-    }
-
-    EndClipDisplayItem(const DisplayItemClientWrapper& client, Type type)
-        : PairedEndDisplayItem(client, type)
-    {
-        ASSERT(isEndClipType(type));
-    }
-
     virtual void replay(GraphicsContext&) override;
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override;