Optimize scroll adjustment for paint invalidation

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007, 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 511 matching lines @@
                       LayoutObject* endChild,
                       bool fullRemoveInsert = false) {
     moveChildrenTo(toBoxModelObject, startChild, endChild, 0, fullRemoveInsert);
   }
   virtual void moveChildrenTo(LayoutBoxModelObject* toBoxModelObject,
                               LayoutObject* startChild,
                               LayoutObject* endChild,
                               LayoutObject* beforeChild,
                               bool fullRemoveInsert = false);
 
+  // Non-composited scrolling should be included in the bounds of scrolled
+  // items. Since mapToVisualRectInAncestorSpace does not include scrolling of
+  // the ancestor, we need to add it back in after.
+  IntSize scrollAdjustmentForPaintInvalidation() const;
+
  private:
   void createLayer();
 
   LayoutUnit computedCSSPadding(const Length&) const;
   bool isBoxModelObject() const final { return true; }
 
   LayoutBoxModelObjectRareData& ensureRareData() {
     if (!m_rareData)
       m_rareData = WTF::makeUnique<LayoutBoxModelObjectRareData>();
     return *m_rareData.get();
   }
 
   // The PaintLayer associated with this object. |m_layer| can be nullptr
   // depending on the return value of layerTypeRequired().
   std::unique_ptr<PaintLayer> m_layer;
 
   std::unique_ptr<LayoutBoxModelObjectRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBoxModelObject, isBoxModelObject());
 
 }  // namespace blink
 
 #endif  // LayoutBoxModelObject_h