WIP for display item list backed by ListContainer

Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h

Index: Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h
diff --git a/Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h b/Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h
index 8b1a948537c3e05cb1c7b83f9c2642ea8f1bfb1a..42d4b84eaf682b73470204dffacbf236036b63ce 100644
--- a/Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h
+++ b/Source/platform/graphics/paint/FixedPositionContainerDisplayItem.h
@@ -7,41 +7,18 @@
 
 #include "platform/geometry/LayoutSize.h"
 #include "platform/graphics/paint/DisplayItem.h"
-#include "wtf/FastAllocBase.h"
 #include "wtf/PassOwnPtr.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT BeginFixedPositionContainerDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(BeginFixedPositionContainerDisplayItem);
 public:
-    static PassOwnPtr<BeginFixedPositionContainerDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new BeginFixedPositionContainerDisplayItem(client));
-    }
-
-    BeginFixedPositionContainerDisplayItem(const DisplayItemClientWrapper& client)
-        : PairedBeginDisplayItem(client, BeginFixedPositionContainer)
-    {
-    }
-
     virtual void replay(GraphicsContext&) override final { }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;
 };
 
 class PLATFORM_EXPORT EndFixedPositionContainerDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndFixedPositionContainerDisplayItem);
 public:
-    static PassOwnPtr<EndFixedPositionContainerDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new EndFixedPositionContainerDisplayItem(client));
-    }
-
-    EndFixedPositionContainerDisplayItem(const DisplayItemClientWrapper& client)
-        : PairedEndDisplayItem(client, EndFixedPositionContainer)
-    {
-    }
-
     virtual void replay(GraphicsContext&) override final { }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;