Blink-side contiguous allocation of display items.

Source/core/paint/SubtreeRecorder.cpp

Index: Source/core/paint/SubtreeRecorder.cpp
diff --git a/Source/core/paint/SubtreeRecorder.cpp b/Source/core/paint/SubtreeRecorder.cpp
index 7597f1b9429cf7b3ac061c0c1887019658615e58..937c2152610af30df8f5961309c846bb29755261 100644
--- a/Source/core/paint/SubtreeRecorder.cpp
+++ b/Source/core/paint/SubtreeRecorder.cpp
@@ -31,7 +31,7 @@ SubtreeRecorder::~SubtreeRecorder()
         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()
@@ -40,7 +40,7 @@ void SubtreeRecorder::begin()
         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;
 }