[Slimming Paint] Blink-side contiguous allocation of display items.

Source/core/paint/LayerClipRecorder.cpp

Index: Source/core/paint/LayerClipRecorder.cpp
diff --git a/Source/core/paint/LayerClipRecorder.cpp b/Source/core/paint/LayerClipRecorder.cpp
index 8ed407eb3a00945912f0a74413a992922bf1cfe9..4b1c9857aa6fdaf79304b2368c425c0a9683ff5d 100644
--- a/Source/core/paint/LayerClipRecorder.cpp
+++ b/Source/core/paint/LayerClipRecorder.cpp
@@ -24,16 +24,16 @@ LayerClipRecorder::LayerClipRecorder(GraphicsContext& graphicsContext, const Lay
     , m_clipType(clipType)
 {
     IntRect snappedClipRect = pixelSnappedIntRect(clipRect.rect());
-    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(layoutObject, clipType, snappedClipRect);
+    ClipDisplayItem clipDisplayItem(layoutObject, clipType, snappedClipRect);
     if (localPaintingInfo && clipRect.hasRadius())
-        collectRoundedRectClips(*layoutObject.layer(), *localPaintingInfo, graphicsContext, fragmentOffset, paintFlags, rule, clipDisplayItem->roundedRectClips());
+        collectRoundedRectClips(*layoutObject.layer(), *localPaintingInfo, graphicsContext, fragmentOffset, paintFlags, rule, clipDisplayItem.roundedRectClips());
     if (!RuntimeEnabledFeatures::slimmingPaintEnabled()) {
-        clipDisplayItem->replay(graphicsContext);
+        clipDisplayItem.replay(graphicsContext);
     } else {
         ASSERT(m_graphicsContext.displayItemList());
         if (m_graphicsContext.displayItemList()->displayItemConstructionIsDisabled())
             return;
-        m_graphicsContext.displayItemList()->add(clipDisplayItem.release());
+        m_graphicsContext.displayItemList()->add(clipDisplayItem);
     }
 }
 
@@ -83,8 +83,8 @@ LayerClipRecorder::~LayerClipRecorder()
         if (m_graphicsContext.displayItemList()->displayItemConstructionIsDisabled())
             return;
         DisplayItem::Type endType = DisplayItem::clipTypeToEndClipType(m_clipType);
-        OwnPtr<EndClipDisplayItem> endClip = EndClipDisplayItem::create(m_layoutObject, endType);
-        m_graphicsContext.displayItemList()->add(endClip.release());
+        EndClipDisplayItem endClip(m_layoutObject, endType);
+        m_graphicsContext.displayItemList()->add(endClip);
     } else {
         m_graphicsContext.restore();
     }