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

third_party/WebKit/Source/core/layout/LayoutTableSection.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, 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 935 matching lines @@
     ASSERT(!needsLayout());
 
     LayoutAnalyzer::Scope analyzer(*this);
 
     // FIXME: Changing the height without a layout can change the overflow so it seems wrong.
 
     unsigned totalRows = m_grid.size();
 
     // Set the width of our section now.  The rows will also be this width.
     setLogicalWidth(table()->contentLogicalWidth());
-    m_overflow.clear();
-    m_overflowingCells.clear();
-    m_forceSlowPaintPathWithOverflowingCell = false;
 
     int vspacing = table()->vBorderSpacing();
     unsigned nEffCols = table()->numEffectiveColumns();
 
     LayoutState state(*this, locationOffset());
 
     for (unsigned r = 0; r < totalRows; r++) {
         // Set the row's x/y position and width/height.
         LayoutTableRow* rowLayoutObject = m_grid[r].rowLayoutObject;
         if (rowLayoutObject) {
             rowLayoutObject->setLocation(LayoutPoint(0, m_rowPos[r]));
             rowLayoutObject->setLogicalWidth(logicalWidth());
             rowLayoutObject->setLogicalHeight(LayoutUnit(m_rowPos[r + 1] - m_rowPos[r] - vspacing));
             rowLayoutObject->updateLayerTransformAfterLayout();
-            rowLayoutObject->clearAllOverflows();
-            rowLayoutObject->addVisualEffectOverflow();
         }
 
         int rowHeightIncreaseForPagination = 0;
 
         for (unsigned c = 0; c < nEffCols; c++) {
             CellStruct& cs = cellAt(r, c);
             LayoutTableCell* cell = cs.primaryCell();
 
             if (!cell || cs.inColSpan)
                 continue;
@@ skipping 70 matching lines @@
                 // FIXME: Pagination might have made us change size. For now just shrink or grow the cell to fit without doing a relayout.
                 // We'll also do a basic increase of the row height to accommodate the cell if it's bigger, but this isn't quite right
                 // either. It's at least stable though and won't result in an infinite # of relayouts that may never stabilize.
                 LayoutUnit oldLogicalHeight = cell->logicalHeight();
                 if (oldLogicalHeight > rHeight)
                     rowHeightIncreaseForPagination = std::max<int>(rowHeightIncreaseForPagination, oldLogicalHeight - rHeight);
                 cell->setLogicalHeight(LayoutUnit(rHeight));
                 cell->computeOverflow(oldLogicalHeight, false);
             }
 
-            if (rowLayoutObject)
-                rowLayoutObject->addOverflowFromCell(cell);
-
             LayoutSize childOffset(cell->location() - oldCellRect.location());
             if (childOffset.width() || childOffset.height()) {
                 // If the child moved, we have to issue paint invalidations to it as well as any floating/positioned
                 // descendants. An exception is if we need a layout. In this case, we know we're going to
                 // issue paint invalidations ourselves (and the child) anyway.
                 if (!table()->selfNeedsLayout())
                     cell->setMayNeedPaintInvalidation();
             }
         }
         if (rowHeightIncreaseForPagination) {
             for (unsigned rowIndex = r + 1; rowIndex <= totalRows; rowIndex++)
                 m_rowPos[rowIndex] += rowHeightIncreaseForPagination;
             for (unsigned c = 0; c < nEffCols; ++c) {
                 Vector<LayoutTableCell*, 1>& cells = cellAt(r, c).cells;
                 for (size_t i = 0; i < cells.size(); ++i) {
                     LayoutUnit oldLogicalHeight = cells[i]->logicalHeight();
                     cells[i]->setLogicalHeight(oldLogicalHeight + rowHeightIncreaseForPagination);
                     cells[i]->computeOverflow(oldLogicalHeight, false);
                 }
             }
         }
+        if (rowLayoutObject)
+            rowLayoutObject->recalculateOverflow();
     }
 
     ASSERT(!needsLayout());
 
     setLogicalHeight(LayoutUnit(m_rowPos[totalRows]));
 
     computeOverflowFromCells(totalRows, nEffCols);
 }
 
 void LayoutTableSection::computeOverflowFromCells()
 {
     unsigned totalRows = m_grid.size();
     unsigned nEffCols = table()->numEffectiveColumns();
     computeOverflowFromCells(totalRows, nEffCols);
 }
 
 void LayoutTableSection::computeOverflowFromCells(unsigned totalRows, unsigned nEffCols)

[Xianzhu, 2016/04/15 20:48:51]

Can row overflow contributing section overflow, for example, when some row has
outline?

 {
     unsigned totalCellsCount = nEffCols * totalRows;
     unsigned maxAllowedOverflowingCellsCount = totalCellsCount < gMinTableSizeToUseFastPaintPathWithOverflowingCell ? 0 : gMaxAllowedOverflowingCellRatioForFastPaintPath * totalCellsCount;
 
+    m_overflow.clear();
+    m_overflowingCells.clear();
+    m_forceSlowPaintPathWithOverflowingCell = false;
 #if ENABLE(ASSERT)
     bool hasOverflowingCell = false;
 #endif
     // Now that our height has been determined, add in overflow from cells.
     for (unsigned r = 0; r < totalRows; r++) {
         for (unsigned c = 0; c < nEffCols; c++) {
             CellStruct& cs = cellAt(r, c);
             LayoutTableCell* cell = cs.primaryCell();
             if (!cell || cs.inColSpan)
                 continue;
@@ skipping 11 matching lines @@
                     // The slow path does not make any use of the overflowing cells info, don't hold on to the memory.
                     m_overflowingCells.clear();
                 }
             }
         }
     }
 
     ASSERT(hasOverflowingCell == this->hasOverflowingCell());
 }
 
+bool LayoutTableSection::recalcChildOverflowAfterStyleChange()
+{
+    ASSERT(childNeedsOverflowRecalcAfterStyleChange());
+    clearChildNeedsOverflowRecalcAfterStyleChange();
+    unsigned totalRows = m_grid.size();
+    unsigned numEffCols = table()->numEffectiveColumns();
+    bool childrenOverflowChanged = false;
+    for (unsigned r = 0; r < totalRows; r++) {
+        LayoutTableRow* rowLayouter = rowLayoutObjectAt(r);
+        if (!rowLayouter || !rowLayouter->childNeedsOverflowRecalcAfterStyleChange())
+            continue;
+        rowLayouter->clearChildNeedsOverflowRecalcAfterStyleChange();
+        bool rowChildrenOverflowChanged = false;
+        for (unsigned c = 0; c < numEffCols; c++) {
+            CellStruct& cs = cellAt(r, c);
+            LayoutTableCell* cell = cs.primaryCell();
+            if (!cell || cs.inColSpan || !cell->needsOverflowRecalcAfterStyleChange())
+                continue;
+            rowChildrenOverflowChanged |= cell->recalcOverflowAfterStyleChange();
+        }
+        if (rowChildrenOverflowChanged)
+            rowLayouter->recalculateOverflow();
+        childrenOverflowChanged |= rowChildrenOverflowChanged;
+    }
+    if (childrenOverflowChanged)
+        computeOverflowFromCells(totalRows, numEffCols);
+    return childrenOverflowChanged;
+}
+
 int LayoutTableSection::calcBlockDirectionOuterBorder(BlockBorderSide side) const
 {
     unsigned totalCols = table()->numEffectiveColumns();
     if (!m_grid.size() || !totalCols)
         return 0;
 
     int borderWidth = 0;
 
     const BorderValue& sb = side == BorderBefore ? style()->borderBefore() : style()->borderAfter();
     if (sb.style() == BorderStyleHidden)
@@ skipping 490 matching lines @@
     // FIXME: The table's direction should determine our row's direction, not the section's (see bug 96691).
     if (!style()->isLeftToRightDirection())
         cellLocation.setX(LayoutUnit(table()->effectiveColumnPositions()[table()->numEffectiveColumns()] - table()->effectiveColumnPositions()[table()->absoluteColumnToEffectiveColumn(cell->absoluteColumnIndex() + cell->colSpan())] + horizontalBorderSpacing));
     else
         cellLocation.setX(LayoutUnit(table()->effectiveColumnPositions()[effectiveColumn] + horizontalBorderSpacing));
 
     cell->setLogicalLocation(cellLocation);
 }
 
 } // namespace blink