[SPv2] Stop recording paired display items (except for subsequence markers)

third_party/WebKit/Source/core/paint/ScrollRecorder.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 "core/paint/ScrollRecorder.h"
 
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "platform/graphics/paint/ScrollDisplayItem.h"
 
 namespace blink {
 
 ScrollRecorder::ScrollRecorder(GraphicsContext& context,
                                const DisplayItemClient& client,
                                DisplayItem::Type type,
                                const IntSize& currentOffset)
     : m_client(client), m_beginItemType(type), m_context(context) {
+  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+    return;
   m_context.getPaintController().createAndAppend<BeginScrollDisplayItem>(
       m_client, m_beginItemType, currentOffset);
 }
 
 ScrollRecorder::ScrollRecorder(GraphicsContext& context,
                                const DisplayItemClient& client,
                                PaintPhase phase,
                                const IntSize& currentOffset)
     : ScrollRecorder(context,
                      client,
                      DisplayItem::paintPhaseToScrollType(phase),
                      currentOffset) {}
 
 ScrollRecorder::~ScrollRecorder() {
+  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+    return;
   m_context.getPaintController().endItem<EndScrollDisplayItem>(
       m_client, DisplayItem::scrollTypeToEndScrollType(m_beginItemType));
 }
 
 }  // namespace blink