Generate scroll/clip display item hierarchy for SPv2

Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2090 matching lines @@
 
     IntSize offset = paintInfo.offsetFromLayoutObject;
     AffineTransform translation;
     translation.translate(-offset.width(), -offset.height());
     TransformRecorder transformRecorder(*context, *this, translation);
 
     // The dirtyRect is in the coords of the painting root.
     IntRect dirtyRect(clip);
     dirtyRect.move(offset);
 
-    if (!(paintLayerFlags & PaintLayerPaintingOverflowContents)) {
+    if (!(paintLayerFlags & PaintLayerPaintingOverflowContents) && !RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
         LayoutRect bounds = paintInfo.compositedBounds;
         bounds.move(paintInfo.paintLayer->subpixelAccumulation());
         dirtyRect.intersect(pixelSnappedIntRect(bounds));
     } else {
         dirtyRect.move(roundedIntSize(paintInfo.paintLayer->subpixelAccumulation()));
     }
 
 #if ENABLE(ASSERT)
     paintInfo.paintLayer->layoutObject()->assertSubtreeIsLaidOut();
 #endif
@@ skipping 275 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink