Optimize collapsed border painting

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

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2009, 2013 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
@@ skipping 16 matching lines @@
 
 #include "core/CoreExport.h"
 #include "core/layout/LayoutTable.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 // This variable is used to balance the memory consumption vs the paint invalidation time on big tables.
 const float gMaxAllowedOverflowingCellRatioForFastPaintPath = 0.1f;
 
-enum CollapsedBorderSide {
-    CBSBefore,
-    CBSAfter,
-    CBSStart,
-    CBSEnd
-};
-
 // Helper class for paintObject.
 class CellSpan {
     STACK_ALLOCATED();
 public:
     CellSpan(unsigned start, unsigned end)
         : m_start(start)
         , m_end(end)
     {
     }
 
@@ skipping 217 matching lines @@
             recalcCells();
     }
 
     bool needsCellRecalc() const { return m_needsCellRecalc; }
     void setNeedsCellRecalc();
 
     LayoutUnit rowBaseline(unsigned row) { return m_grid[row].baseline; }
 
     void rowLogicalHeightChanged(LayoutTableRow*);
 
-    void removeCachedCollapsedBorders(const LayoutTableCell*);
-    // Returns true if any collapsed borders of the cell changed.
-    bool setCachedCollapsedBorder(const LayoutTableCell*, CollapsedBorderSide, const CollapsedBorderValue&);
-    const CollapsedBorderValue& cachedCollapsedBorder(const LayoutTableCell*, CollapsedBorderSide) const;
-
     // distributeExtraLogicalHeightToRows methods return the *consumed* extra logical height.
     // FIXME: We may want to introduce a structure holding the in-flux layout information.
     int distributeExtraLogicalHeightToRows(int extraLogicalHeight);
 
     static LayoutTableSection* createAnonymousWithParent(const LayoutObject*);
     LayoutBox* createAnonymousBoxWithSameTypeAs(const LayoutObject* parent) const override
     {
         return createAnonymousWithParent(parent);
     }
 
@@ skipping 100 matching lines @@
     // and m_forceSlowPaintPathWithOverflowingCell will be set to save memory.
     HashSet<LayoutTableCell*> m_overflowingCells;
     bool m_forceSlowPaintPathWithOverflowingCell;
 
     // This boolean tracks if we have cells overlapping due to rowspan / colspan
     // (see class comment above about when it could appear).
     //
     // The use is to disable a painting optimization where we just paint the
     // invalidated cells.
     bool m_hasMultipleCellLevels;
-
-    // This map holds the collapsed border values for cells with collapsed borders.
-    // It is held at LayoutTableSection level to spare memory consumption by table cells.
-    using CellsCollapsedBordersMap = HashMap<std::pair<const LayoutTableCell*, int>, CollapsedBorderValue>;
-    CellsCollapsedBordersMap m_cellsCollapsedBorders;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableSection, isTableSection());
 
 } // namespace blink
 
 #endif // LayoutTableSection_h