Blink-side contiguous allocation of display items.

Source/platform/graphics/paint/DrawingRecorder.cpp

Index: Source/platform/graphics/paint/DrawingRecorder.cpp
diff --git a/Source/platform/graphics/paint/DrawingRecorder.cpp b/Source/platform/graphics/paint/DrawingRecorder.cpp
index 34b43b3b99dd704803043d5ba30baaffd5a1f975..44b81310985d83a8a5bb7dc2b5aac9e97a364b08 100644
--- a/Source/platform/graphics/paint/DrawingRecorder.cpp
+++ b/Source/platform/graphics/paint/DrawingRecorder.cpp
@@ -91,13 +91,13 @@ DrawingRecorder::~DrawingRecorder()
                 m_displayItemClient.debugName().utf8().data());
         }
 #endif
-        m_context.displayItemList()->add(CachedDisplayItem::create(m_displayItemClient, DisplayItem::drawingTypeToCachedType(m_displayItemType)));
+        m_context.displayItemList()->createAndAppendIfNeeded<CachedDisplayItem>(m_displayItemClient, DisplayItem::drawingTypeToCachedType(m_displayItemType));
     } else {
-        OwnPtr<DrawingDisplayItem> drawingDisplayItem = DrawingDisplayItem::create(m_displayItemClient, m_displayItemType, m_context.endRecording());
 #if ENABLE(ASSERT)
-        drawingDisplayItem->setUnderInvalidationCheckingMode(m_underInvalidationCheckingMode);
+        m_context.displayItemList()->createAndAppendIfNeeded<DrawingDisplayItem>(m_displayItemClient, m_displayItemType, m_context.endRecording(), m_underInvalidationCheckingMode);
+#else
+        m_context.displayItemList()->createAndAppendIfNeeded<DrawingDisplayItem>(m_displayItemClient, m_displayItemType, m_context.endRecording());
 #endif
-        m_context.displayItemList()->add(drawingDisplayItem.release());
     }
 }