Use the original paint invalidation path for sync painting v1

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 366 matching lines @@
         && previousPaintInvalidationRect != this->previousPaintInvalidationRect()
         && !usesCompositedScrolling()
         && hasOverflowClip())
         childTreeWalkState.setForceSubtreeInvalidationRectUpdateWithinContainer();
 
     invalidatePaintOfSubtreesIfNeeded(childTreeWalkState);
 }
 
 void LayoutBoxModelObject::setBackingNeedsPaintInvalidationInRect(const LayoutRect& r, PaintInvalidationReason invalidationReason) const
 {
-    ASSERT(!RuntimeEnabledFeatures::slimmingPaintSynchronizedPaintingEnabled());
+    ASSERT(!RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,
     // so assert but check that the layer is composited.
     ASSERT(compositingState() != NotComposited);
 
     // FIXME: generalize accessors to backing GraphicsLayers so that this code is squashing-agnostic.
     if (layer()->groupedMapping()) {
         LayoutRect paintInvalidationRect = r;
         if (GraphicsLayer* squashingLayer = layer()->groupedMapping()->squashingLayer()) {
             // Note: the subpixel accumulation of layer() does not need to be added here. It is already taken into account.
@@ skipping 659 matching lines @@
     if (rootElementStyle->hasBackground())
         return false;
 
     if (node() != document().firstBodyElement())
         return false;
 
     return true;
 }
 
 } // namespace blink