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

Source/platform/graphics/paint/ClipRecorder.cpp

 // Copyright 2014 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 "platform/graphics/paint/ClipRecorder.h"
 
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/ClipDisplayItem.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 
 namespace blink {
 
 ClipRecorder::ClipRecorder(GraphicsContext& context, const DisplayItemClientWrapper& client, DisplayItem::Type type, const LayoutRect& clipRect, SkRegion::Op operation)
     : m_client(client)
     , m_context(context)
     , m_type(type)
 {
+    ClipDisplayItem clipDisplayItem(m_client, type, pixelSnappedIntRect(clipRect), operation);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(m_context.displayItemList());
         if (m_context.displayItemList()->displayItemConstructionIsDisabled())
             return;
-        m_context.displayItemList()->add(ClipDisplayItem::create(m_client, type, pixelSnappedIntRect(clipRect), operation));
+        m_context.displayItemList()->add(clipDisplayItem);
     } else {
-        ClipDisplayItem clipDisplayItem(m_client, type, pixelSnappedIntRect(clipRect), operation);
         clipDisplayItem.replay(m_context);
     }
 }
 
 ClipRecorder::~ClipRecorder()
 {
     DisplayItem::Type endType = DisplayItem::clipTypeToEndClipType(m_type);
+    EndClipDisplayItem endClipDisplayItem(m_client, endType);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         ASSERT(m_context.displayItemList());
         if (m_context.displayItemList()->displayItemConstructionIsDisabled())
             return;
-        m_context.displayItemList()->add(EndClipDisplayItem::create(m_client, endType));
+        m_context.displayItemList()->add(endClipDisplayItem);
     } else {
-        EndClipDisplayItem endClipDisplayItem(m_client, endType);
         endClipDisplayItem.replay(m_context);
     }
 }
 
 } // namespace blink