Blink-side contiguous allocation of display items.

Source/core/paint/BoxClipper.cpp

Index: Source/core/paint/BoxClipper.cpp
diff --git a/Source/core/paint/BoxClipper.cpp b/Source/core/paint/BoxClipper.cpp
index ce1de5652c9232df953bec572020b00fd471b139..34361623f6b98d4eded1179e3fc03a84175b9378 100644
--- a/Source/core/paint/BoxClipper.cpp
+++ b/Source/core/paint/BoxClipper.cpp
@@ -52,19 +52,23 @@ BoxClipper::BoxClipper(LayoutBox& box, const PaintInfo& paintInfo, const LayoutP
             return;
     }
 
-    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
-        m_clipType = m_paintInfo.displayItemTypeForClipping();
-
-    OwnPtr<ClipDisplayItem> clipDisplayItem = ClipDisplayItem::create(m_box, m_clipType, pixelSnappedIntRect(clipRect));
-    if (hasBorderRadius)
-        clipDisplayItem->roundedRectClips().append(clipRoundedRect);
-
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(m_paintInfo.context->displayItemList());
-        if (!m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled())
-            m_paintInfo.context->displayItemList()->add(clipDisplayItem.release());
+        m_clipType = m_paintInfo.displayItemTypeForClipping();
+        if (!m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled()) {
+            if (hasBorderRadius)
+                m_paintInfo.context->displayItemList()->createAndAppendIfNeeded<ClipDisplayItem>(m_box, m_clipType, pixelSnappedIntRect(clipRect), clipRoundedRect);
+            else
+                m_paintInfo.context->displayItemList()->createAndAppendIfNeeded<ClipDisplayItem>(m_box, m_clipType, pixelSnappedIntRect(clipRect));
+        }
     } else {
-        clipDisplayItem->replay(*paintInfo.context);
+        if (hasBorderRadius) {
+            ClipDisplayItem clipDisplayItem(m_box, m_clipType, pixelSnappedIntRect(clipRect), clipRoundedRect);
+            clipDisplayItem.replay(*paintInfo.context);
+        } else {
+            ClipDisplayItem clipDisplayItem(m_box, m_clipType, pixelSnappedIntRect(clipRect));
+            clipDisplayItem.replay(*paintInfo.context);
+        }
     }
 
     m_pushedClip = true;
@@ -81,9 +85,8 @@ BoxClipper::~BoxClipper()
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         if (m_paintInfo.context->displayItemList()->displayItemConstructionIsDisabled())
             return;
-        OwnPtr<EndClipDisplayItem> endClipDisplayItem = EndClipDisplayItem::create(m_box, endType);
         ASSERT(m_paintInfo.context->displayItemList());
-        m_paintInfo.context->displayItemList()->add(endClipDisplayItem.release());
+        m_paintInfo.context->displayItemList()->createAndAppendIfNeeded<EndClipDisplayItem>(m_box, endType);
     } else {
         EndClipDisplayItem endClipDisplayItem(m_box, endType);
         endClipDisplayItem.replay(*m_paintInfo.context);