Table cells, rows, sections or column (groups) don't support margins.

Source/core/layout/LayoutTableRow.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.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 149 matching lines @@
     ASSERT(needsLayout());
     LayoutAnalyzer::Scope analyzer(*this);
 
     // Table rows do not add translation.
     LayoutState state(*this, LayoutSize());
 
     for (LayoutTableCell* cell = firstCell(); cell; cell = cell->nextCell()) {
         SubtreeLayoutScope layouter(*cell);
         if (!cell->needsLayout())
             cell->markForPaginationRelayoutIfNeeded(layouter);
-        if (cell->needsLayout()) {
-            cell->computeAndSetBlockDirectionMargins(table());
+        if (cell->needsLayout())
             cell->layout();
-        }
     }
 
     m_overflow.clear();
     addVisualEffectOverflow();
     // We do not call addOverflowFromCell here. The cell are laid out to be
     // measured above and will be sized correctly in a follow-up phase.
 
     // We only ever need to issue paint invalidations if our cells didn't, which means that they didn't need
     // layout, so we know that our bounds didn't change. This code is just making up for
     // the fact that we did not invalidate paints in setStyle() because we had a layout hint.
@@ skipping 68 matching lines @@
     // The cell and the row share the section's coordinate system. However
     // the visual overflow should be determined in the coordinate system of
     // the row, that's why we shift it below.
     LayoutUnit cellOffsetLogicalTopDifference = cell->location().y() - location().y();
     cellVisualOverflowRect.move(0, cellOffsetLogicalTopDifference);
 
     addVisualOverflow(cellVisualOverflowRect);
 }
 
 } // namespace blink