Blink-side contiguous allocation of display items.

Source/core/paint/LayerFixedPositionRecorder.cpp

Index: Source/core/paint/LayerFixedPositionRecorder.cpp
diff --git a/Source/core/paint/LayerFixedPositionRecorder.cpp b/Source/core/paint/LayerFixedPositionRecorder.cpp
index 966c99925587a33f5481c0efa860ab0e7d717692..1916e8c87adf522c8d3a3839fa918c701e6dfd45 100644
--- a/Source/core/paint/LayerFixedPositionRecorder.cpp
+++ b/Source/core/paint/LayerFixedPositionRecorder.cpp
@@ -27,13 +27,13 @@ LayerFixedPositionRecorder::LayerFixedPositionRecorder(GraphicsContext& graphics
         return;
 
     if (m_isFixedPosition)
-        m_graphicsContext.displayItemList()->add(BeginFixedPositionDisplayItem::create(m_layoutObject));
+        m_graphicsContext.displayItemList()->createAndAppendIfNeeded<BeginFixedPositionDisplayItem>(m_layoutObject);
 
     // TODO(trchen): Adding a pair of display items on every transformed
     // element can be expensive. Investigate whether we can optimize out some
     // of them if applicable.
     if (m_isFixedPositionContainer)
-        m_graphicsContext.displayItemList()->add(BeginFixedPositionContainerDisplayItem::create(m_layoutObject));
+        m_graphicsContext.displayItemList()->createAndAppendIfNeeded<BeginFixedPositionContainerDisplayItem>(m_layoutObject);
 }
 
 LayerFixedPositionRecorder::~LayerFixedPositionRecorder()
@@ -45,10 +45,10 @@ LayerFixedPositionRecorder::~LayerFixedPositionRecorder()
         return;
 
     if (m_isFixedPositionContainer)
-        m_graphicsContext.displayItemList()->add(EndFixedPositionContainerDisplayItem::create(m_layoutObject));
+        m_graphicsContext.displayItemList()->createAndAppendIfNeeded<EndFixedPositionContainerDisplayItem>(m_layoutObject);
 
     if (m_isFixedPosition)
-        m_graphicsContext.displayItemList()->add(EndFixedPositionDisplayItem::create(m_layoutObject));
+        m_graphicsContext.displayItemList()->createAndAppendIfNeeded<EndFixedPositionDisplayItem>(m_layoutObject);
 }
 
 } // namespace blink