Blink-side contiguous allocation of display items.

Source/core/paint/SubtreeRecorder.cpp

 // 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.
 
 #include "config.h"
 #include "core/paint/SubtreeRecorder.h"
 
 #include "core/layout/LayoutObject.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
@@ skipping 13 matching lines @@
 
     ASSERT(m_displayItemList);
 }
 
 SubtreeRecorder::~SubtreeRecorder()
 {
     if (!RuntimeEnabledFeatures::slimmingPaintEnabled())
         return;
 
     if (m_begun)
-        m_displayItemList->add(EndSubtreeDisplayItem::create(m_subtreeRoot, DisplayItem::paintPhaseToEndSubtreeType(m_paintPhase)));
+        m_displayItemList->createAndAppendIfNeeded<EndSubtreeDisplayItem>(m_subtreeRoot, DisplayItem::paintPhaseToEndSubtreeType(m_paintPhase));
 }
 
 void SubtreeRecorder::begin()
 {
     if (!RuntimeEnabledFeatures::slimmingPaintEnabled())
         return;
     if (m_displayItemList->displayItemConstructionIsDisabled())
         return;
-    m_displayItemList->add(BeginSubtreeDisplayItem::create(m_subtreeRoot, DisplayItem::paintPhaseToBeginSubtreeType(m_paintPhase)));
+    m_displayItemList->createAndAppendIfNeeded<BeginSubtreeDisplayItem>(m_subtreeRoot, DisplayItem::paintPhaseToBeginSubtreeType(m_paintPhase));
     m_begun = true;
 }
 
 } // namespace blink