Calculate paint invalidation rect for scrollbars

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

 /*
  * Copyright (C) 2008, 2009 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 15 matching lines @@
 #ifndef LayoutScrollbar_h
 #define LayoutScrollbar_h
 
 #include "core/style/ComputedStyleConstants.h"
 #include "platform/heap/Handle.h"
 #include "platform/scroll/Scrollbar.h"
 #include "wtf/HashMap.h"
 
 namespace blink {
 
+class ComputedStyle;
+class LayoutBox;
+class LayoutBoxModelObject;
+class LayoutScrollbarPart;
 class LocalFrame;
 class Node;
-class LayoutBox;
-class LayoutScrollbarPart;
-class ComputedStyle;
+class PaintInvalidationState;
 
 class LayoutScrollbar final : public Scrollbar {
 public:
     static PassRefPtrWillBeRawPtr<Scrollbar> createCustomScrollbar(ScrollableArea*, ScrollbarOrientation, Node*, LocalFrame* owningFrame = nullptr);
     ~LayoutScrollbar() override;
 
     LayoutBox* owningLayoutObject() const;
     LayoutBox* owningLayoutObjectWithinFrame() const;
 
     IntRect buttonRect(ScrollbarPart) const;
     IntRect trackRect(int startLength, int endLength) const;
     IntRect trackPieceRectWithMargins(ScrollbarPart, const IntRect&) const;
 
     int minimumThumbLength() const;
 
     bool isOverlayScrollbar() const override { return false; }
 
     LayoutScrollbarPart* getPart(ScrollbarPart partType) { return m_parts.get(partType); }
     const LayoutScrollbarPart* getPart(ScrollbarPart partType) const { return m_parts.get(partType); }
 
-    void invalidateRect(const IntRect&) override;
+    void invalidateDisplayItemClientsOfScrollbarParts(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutRect& paintInvalidationRect);
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     LayoutScrollbar(ScrollableArea*, ScrollbarOrientation, Node*, LocalFrame*);
 
 private:
     friend class Scrollbar;
 
     void setParent(Widget*) override;
@@ skipping 20 matching lines @@
     RawPtrWillBeMember<LocalFrame> m_owningFrame;
 
     HashMap<unsigned, LayoutScrollbarPart*> m_parts;
 };
 
 DEFINE_TYPE_CASTS(LayoutScrollbar, ScrollbarThemeClient, scrollbar, scrollbar->isCustomScrollbar(), scrollbar.isCustomScrollbar());
 
 } // namespace blink
 
 #endif // LayoutScrollbar_h