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

third_party/WebKit/Source/core/layout/LayoutTable.cpp

 /*
  * 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, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 396 matching lines @@
 
     for (LayoutTableSection* section = topSection(); section; section = sectionBelow(section)) {
         section->layoutIfNeeded();
         section->layoutRows();
         section->computeOverflowFromCells();
         section->updateLayerTransformAfterLayout();
         section->addVisualEffectOverflow();
     }
 }
 
+bool LayoutTable::recalcChildOverflowAfterStyleChange()
+{
+    ASSERT(childNeedsOverflowRecalcAfterStyleChange());
+    clearChildNeedsOverflowRecalcAfterStyleChange();
+    bool childrenOverflowChanged = false;
+    for (LayoutTableSection* section = topSection(); section; section = sectionBelow(section)) {
+        if (!section->childNeedsOverflowRecalcAfterStyleChange())
+            continue;
+        childrenOverflowChanged |= section->recalcChildOverflowAfterStyleChange();
+    }
+    return childrenOverflowChanged;
+}
+
 void LayoutTable::layout()
 {
     ASSERT(needsLayout());
     LayoutAnalyzer::Scope analyzer(*this);
 
     if (simplifiedLayout())
         return;
 
     // Note: LayoutTable is handled differently than other LayoutBlocks and the LayoutScope
     //       must be created before the table begins laying out.
@@ skipping 1034 matching lines @@
 
 LayoutUnit LayoutTable::paddingRight() const
 {
     if (collapseBorders())
         return LayoutUnit();
 
     return LayoutBlock::paddingRight();
 }
 
 } // namespace blink