Adding or changing any of box-shadow, outline, or border-image-outset does not need a layout..

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 105 matching lines @@
 
     void addChild(LayoutObject* child, LayoutObject* beforeChild = nullptr) override;
 
     int firstLineBoxBaseline() const override;
 
     void addCell(LayoutTableCell*, LayoutTableRow*);
 
     int calcRowLogicalHeight();
     void layoutRows();
     void computeOverflowFromCells();
+    bool recalcChildOverflowAfterStyleChange();
 
     LayoutTable* table() const { return toLayoutTable(parent()); }
 
     typedef Vector<LayoutTableCell*, 2> SpanningLayoutTableCells;
 
     // CellStruct represents the cells that occupy an (N, M) position in the
     // table grid.
     struct CellStruct {
         DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
     public:
@@ skipping 281 matching lines @@
     // Invisible borders are never stored in this map.
     using CellsCollapsedBordersMap = HashMap<std::pair<const LayoutTableCell*, int>, CollapsedBorderValue>;
     CellsCollapsedBordersMap m_cellsCollapsedBorders;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableSection, isTableSection());
 
 } // namespace blink
 
 #endif // LayoutTableSection_h