Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/FixedPositionDisplayItem.h

 // Copyright 2015 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 FixedPositionDisplayItem_h
 #define FixedPositionDisplayItem_h
 
 #include "platform/geometry/LayoutSize.h"
 #include "platform/graphics/paint/DisplayItem.h"
-#include "wtf/FastAllocBase.h"
-#include "wtf/PassOwnPtr.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT BeginFixedPositionDisplayItem : public PairedBeginDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(BeginFixedPositionDisplayItem);
 public:
-    static PassOwnPtr<BeginFixedPositionDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new BeginFixedPositionDisplayItem(client));
-    }
-
     BeginFixedPositionDisplayItem(const DisplayItemClientWrapper& client)
         : PairedBeginDisplayItem(client, BeginFixedPosition)
     {
     }
 
     virtual void replay(GraphicsContext&) override final { }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;
+    void appendByMoving(DisplayItems&) override;
 };
 
 class PLATFORM_EXPORT EndFixedPositionDisplayItem : public PairedEndDisplayItem {
-    WTF_MAKE_FAST_ALLOCATED(EndFixedPositionDisplayItem);
 public:
-    static PassOwnPtr<EndFixedPositionDisplayItem> create(const DisplayItemClientWrapper& client)
-    {
-        return adoptPtr(new EndFixedPositionDisplayItem(client));
-    }
-
     EndFixedPositionDisplayItem(const DisplayItemClientWrapper& client)
         : PairedEndDisplayItem(client, EndFixedPosition)
     {
     }
 
     virtual void replay(GraphicsContext&) override final { }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final;
+    void appendByMoving(DisplayItems&) override;
 
 private:
 #if ENABLE(ASSERT)
     virtual bool isEndAndPairedWith(DisplayItem::Type otherType) const override final { return otherType == BeginFixedPosition; }
 #endif
 };
 
 } // namespace blink
 
 #endif // FixedPositionDisplayItem_h