Row with only spanning cells have a height of 0.

Source/core/rendering/RenderTableSection.cpp

Index: Source/core/rendering/RenderTableSection.cpp
diff --git a/Source/core/rendering/RenderTableSection.cpp b/Source/core/rendering/RenderTableSection.cpp
index b49f47f6987963472b955849aa78f06dab026038..a69ff0153b77a978f987b0e9bd55ea138863b1c2 100644
--- a/Source/core/rendering/RenderTableSection.cpp
+++ b/Source/core/rendering/RenderTableSection.cpp
@@ -253,6 +253,29 @@ void RenderTableSection::addCell(RenderTableCell* cell, RenderTableRow* row)
     cell->setCol(table()->effColToCol(col));
 }
 
+unsigned RenderTableSection::rowHasOnlySpanningCells(unsigned row)
+{
+    ASSERT(row < m_grid.size());

[Julien - ping for review, 2013/09/18 18:39:37]

This ...

[a.suchit, 2013/09/19 08:18:36]

Done.

+
+    if (row >= m_grid.size())

[Julien - ping for review, 2013/09/18 18:39:37]

.. and this are unneeded ...

[a.suchit, 2013/09/19 08:18:36]

Done.

+        return false;
+
+    unsigned totalCols = m_grid[row].row.size();

[Julien - ping for review, 2013/09/18 18:39:37]

... because m_grid[row] calls Vector::at(size_t i) which is implemented as
follows:

RELEASE_ASSERT(i < size());
return Base::buffer()[i];

(The RELEASE_ASSERT is what duplicates both of your statements)

+
+    if (!totalCols)
+        return false;
+
+    for (unsigned col = 0; col < totalCols; col++) {
+        const CellStruct& rowSpanCell = cellAt(row, col);
+
+        // Empty cell would be 1 rowspan cell only if we consider that empty cell is valid cell.

[Julien - ping for review, 2013/09/18 18:39:37]

The more I read this comment the less I understand what you mean. Is an empty
cell a rowspan cell? Is an empty cell a valid cell? What does that even mean to
be a "valid cell"?

[a.suchit, 2013/09/19 08:18:36]

Done.

+        if (rowSpanCell.cells.isEmpty() || rowSpanCell.cells[0]->rowSpan() == 1)

[Julien - ping for review, 2013/09/18 18:39:37]

Nit: I would have separated these 2 conditions so that they are not confused
with each other.

[a.suchit, 2013/09/19 08:18:36]

Done.

+            return false;
+    }
+
+    return true;
+}
+
 void RenderTableSection::populateSpanningRowsHeightFromCell(RenderTableCell* cell, struct SpanningRowsHeight& spanningRowsHeight)
 {
     const unsigned rowSpan = cell->rowSpan();
@@ -264,7 +287,11 @@ void RenderTableSection::populateSpanningRowsHeightFromCell(RenderTableCell* cel
     spanningRowsHeight.totalRowsHeight = 0;
     for (unsigned row = 0; row < rowSpan; row++) {
         unsigned actualRow = row + rowIndex;
+
         spanningRowsHeight.rowHeight[row] = m_rowPos[actualRow + 1] - m_rowPos[actualRow] - borderSpacingForRow(actualRow);
+        if (!spanningRowsHeight.rowHeight[row])
+            spanningRowsHeight.rowWithOnlySpanningCells |= rowHasOnlySpanningCells(actualRow);
+
         spanningRowsHeight.totalRowsHeight += spanningRowsHeight.rowHeight[row];
         spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing -= borderSpacingForRow(actualRow);
     }
@@ -395,6 +422,52 @@ static bool compareRowSpanCellsInHeightDistributionOrder(const RenderTableCell*
     return false;
 }
 
+unsigned RenderTableSection::calcRowHeightHavingOnlySpanningCells(unsigned row)
+{
+    ASSERT(row < m_grid.size());

[Julien - ping for review, 2013/09/18 18:39:37]

Same comment as above, unneeded and should be removed.

[a.suchit, 2013/09/19 08:18:36]

Done.

+    ASSERT(rowHasOnlySpanningCells(row));
+
+    if (row >= m_grid.size())

[Julien - ping for review, 2013/09/18 18:39:37]

Same comment as above, unneeded and should be removed.

[a.suchit, 2013/09/19 08:18:36]

Done.

+        return 0;
+
+    unsigned totalCols = m_grid[row].row.size();
+
+    if (!totalCols)
+        return 0;
+
+    unsigned rowHeight = 0;
+
+    for (unsigned col = 0; col < totalCols; col++) {
+        CellStruct rowSpanCell = cellAt(row, col);

[Julien - ping for review, 2013/09/18 18:39:37]

Again, const reference to avoid an implicit copy! (unfortunately CellStruct
cannot be MAKE_NON_COPYABLE due to Vector :()

[a.suchit, 2013/09/19 08:18:36]

Done.

+        if (rowSpanCell.cells.size() && rowSpanCell.cells[0]->rowSpan() > 1)
+            rowHeight = max(rowHeight, rowSpanCell.cells[0]->logicalHeightForRowSizing() / rowSpanCell.cells[0]->rowSpan());
+    }
+
+    return rowHeight;
+}
+
+void RenderTableSection::updateRowsHeightHavingOnlySpanningCells(RenderTableCell* cell, struct SpanningRowsHeight& spanningRowsHeight)
+{
+    ASSERT(spanningRowsHeight.rowHeight.size());
+
+    int accumulatedPositionIncrease = 0;
+    const unsigned rowSpan = cell->rowSpan();
+    const unsigned rowIndex = cell->rowIndex();
+
+    ASSERT(rowSpan == spanningRowsHeight.rowHeight.size());
+
+    for (unsigned row = 0; row < spanningRowsHeight.rowHeight.size(); row++) {
+        unsigned actualRow = row + rowIndex;
+        if (!spanningRowsHeight.rowHeight[row] && rowHasOnlySpanningCells(actualRow)) {
+            spanningRowsHeight.rowHeight[row] = calcRowHeightHavingOnlySpanningCells(actualRow);
+            accumulatedPositionIncrease += spanningRowsHeight.rowHeight[row];
+        }
+        m_rowPos[actualRow + 1] += accumulatedPositionIncrease;
+    }
+
+    spanningRowsHeight.totalRowsHeight += accumulatedPositionIncrease;
+}
+
 // Distribute rowSpan cell height in rows those comes in rowSpan cell based on the ratio of row's height if
 // 1. RowSpan cell height is greater then the total height of rows in rowSpan cell
 void RenderTableSection::distributeRowSpanHeightToRows(SpanningRenderTableCells& rowSpanCells)
@@ -444,8 +517,13 @@ void RenderTableSection::distributeRowSpanHeightToRows(SpanningRenderTableCells&
 
         populateSpanningRowsHeightFromCell(cell, spanningRowsHeight);
 
-        if (!spanningRowsHeight.totalRowsHeight || spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing <= spanningRowsHeight.totalRowsHeight)
+        if (spanningRowsHeight.rowWithOnlySpanningCells)
+            updateRowsHeightHavingOnlySpanningCells(cell, spanningRowsHeight);
+
+        if (!spanningRowsHeight.totalRowsHeight || spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing <= spanningRowsHeight.totalRowsHeight) {
+            extraHeightToPropagate = m_rowPos[rowIndex + rowSpan] - originalBeforePosition;
             continue;
+        }
 
         int totalPercent = 0;
         int totalAutoRowsHeight = 0;