Revert of Don't include contents visual overflow into paint invalidation rect

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

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 76 matching lines @@
         , m_visualOverflow(visualRect)
     {
     }
 
     const LayoutRect& layoutOverflowRect() const { return m_layoutOverflow; }
     void setLayoutOverflow(const LayoutRect& rect) { m_layoutOverflow = rect; }
     void addLayoutOverflow(const LayoutRect& rect) { uniteLayoutOverflowRect(m_layoutOverflow, rect); }
 
     const LayoutRect& visualOverflowRect() const { return m_visualOverflow; }
     void setVisualOverflow(const LayoutRect& rect) { m_visualOverflow = rect; }
-    void addVisualOverflow(const LayoutRect& rect) { m_visualOverflow.unite(rect); }
+    // TODO(wangxianzhu): Should use normal LayoutRect::unite() which ignores empty rects.
+    void addVisualOverflow(const LayoutRect& rect) { m_visualOverflow.uniteEvenIfEmpty(rect); }
 
     void move(LayoutUnit dx, LayoutUnit dy)
     {
         m_layoutOverflow.move(dx, dy);
         m_visualOverflow.move(dx, dy);
     }
 
 private:
     LayoutRect m_layoutOverflow;
     LayoutRect m_visualOverflow;
@@ skipping 32 matching lines @@
         : m_layoutOverflow(layoutRect)
         , m_selfVisualOverflow(selfVisualOverflowRect)
     {
     }
 
     const LayoutRect& layoutOverflowRect() const { return m_layoutOverflow; }
     void setLayoutOverflow(const LayoutRect& rect) { m_layoutOverflow = rect; }
     void addLayoutOverflow(const LayoutRect& rect) { uniteLayoutOverflowRect(m_layoutOverflow, rect); }
 
     const LayoutRect& selfVisualOverflowRect() const { return m_selfVisualOverflow; }
-    void addSelfVisualOverflow(const LayoutRect& rect) { m_selfVisualOverflow.unite(rect); }
+    // TODO(wangxianzhu): Should use normal LayoutRect::unite() which ignores empty rects.
+    void addSelfVisualOverflow(const LayoutRect& rect) { m_selfVisualOverflow.uniteEvenIfEmpty(rect); }
 
     const LayoutRect& contentsVisualOverflowRect() const { return m_contentsVisualOverflow; }
     void addContentsVisualOverflow(const LayoutRect& rect) { m_contentsVisualOverflow.unite(rect); }
 
     void move(LayoutUnit dx, LayoutUnit dy)
     {
         m_layoutOverflow.move(dx, dy);
         m_selfVisualOverflow.move(dx, dy);
         m_contentsVisualOverflow.move(dx, dy);
     }
 
     LayoutUnit layoutClientAfterEdge() const { return m_layoutClientAfterEdge; }
     void setLayoutClientAfterEdge(LayoutUnit clientAfterEdge) { m_layoutClientAfterEdge = clientAfterEdge; }
 
 private:
     LayoutRect m_layoutOverflow;
     LayoutRect m_selfVisualOverflow;
     LayoutRect m_contentsVisualOverflow;
     LayoutUnit m_layoutClientAfterEdge;
 };
 
 } // namespace blink
 
 #endif // OverflowModel_h