Handling of percent less than 1 while extra height distribution in spanning rows.

Source/core/layout/LayoutTableSection.cpp

Index: Source/core/layout/LayoutTableSection.cpp
diff --git a/Source/core/layout/LayoutTableSection.cpp b/Source/core/layout/LayoutTableSection.cpp
index 29e2a0c609103400515219cc23d2224ab18a3e07..005e41c88d38114a6e8e98b9ad7e54cff80dc80b 100644
--- a/Source/core/layout/LayoutTableSection.cpp
+++ b/Source/core/layout/LayoutTableSection.cpp
@@ -293,14 +293,15 @@ void LayoutTableSection::populateSpanningRowsHeightFromCell(LayoutTableCell* cel
     spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing += borderSpacingForRow(rowIndex + rowSpan - 1);
 }
 
-void LayoutTableSection::distributeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, int totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
+void LayoutTableSection::distributeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, LayoutUnit totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
 {
     if (!extraRowSpanningHeight || !totalPercent)
         return;
 
     const unsigned rowSpan = cell->rowSpan();
     const unsigned rowIndex = cell->rowIndex();
-    int percent = std::min(totalPercent, 100);
+    LayoutUnit percent = 100;
+    percent = std::min(totalPercent, percent);
     const int tableHeight = m_rowPos[m_grid.size()] + extraRowSpanningHeight;
 
     // Our algorithm matches Firefox. Extra spanning height would be distributed Only in first percent height rows
@@ -323,15 +324,18 @@ void LayoutTableSection::distributeExtraRowSpanHeightToPercentRows(LayoutTableCe
     }
 }
 
-// Sometimes the multiplication of the 2 values below will overflow an integer.
-// So we convert the parameters to 'long long' instead of 'int' to avoid the
-// problem in this function.
-static void updatePositionIncreasedWithRowHeight(long long extraHeight, long long rowHeight, long long totalHeight, int& accumulatedPositionIncrease, int& remainder)
+static void updatePositionIncreasedWithRowHeight(int extraHeight, LayoutUnit rowHeight, LayoutUnit totalHeight, int& accumulatedPositionIncrease, int& remainder)
 {
     static_assert(sizeof(long long int) > sizeof(int), "int should be smaller than long long");
 
-    accumulatedPositionIncrease += (extraHeight * rowHeight) / totalHeight;
-    remainder += (extraHeight * rowHeight) % totalHeight;
+    // Multiplication of the 2 values below will overflow in LayoutUnit.
+    // So we converted to 'long long' instead of 'int' to avoid the problem in this function.
+    // Upto 2 digits of rational part is considered for calculation.

[Julien - ping for review, 2015/03/26 17:05:15]

That's a lot of computation, most of which makes little sense.

The comment makes no sense: rowHeight is a LayoutUnit so you're doing a
LayoutUnit multiplication that you cast to int :(

+    long long rHeight = static_cast<int>(rowHeight * 100);
+    long long tHeight = static_cast<int>(totalHeight * 100);
+
+    accumulatedPositionIncrease += (extraHeight * rHeight) / tHeight;
+    remainder += ((extraHeight * rHeight) % tHeight) / 100;
 }
 
 // This is mainly used to distribute whole extra rowspanning height in percent rows when all spanning rows are
@@ -339,7 +343,7 @@ static void updatePositionIncreasedWithRowHeight(long long extraHeight, long lon
 // Distributing whole extra rowspanning height in percent rows based on the ratios of percent because this method works
 // same as percent distribution when only percent rows are present and percent is 100. Also works perfectly fine when
 // percent is not equal to 100.
-void LayoutTableSection::distributeWholeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, int totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
+void LayoutTableSection::distributeWholeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, LayoutUnit totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
 {
     if (!extraRowSpanningHeight || !totalPercent)
         return;
@@ -358,7 +362,7 @@ void LayoutTableSection::distributeWholeExtraRowSpanHeightToPercentRows(LayoutTa
             // is equvalent to divisor then 1 unit increased in row position.
             // Note that this algorithm is biased towards adding more space towards the lower rows.
             if (remainder >= totalPercent) {
-                remainder -= totalPercent;
+                remainder = remainder - totalPercent;
                 accumulatedPositionIncrease++;
             }
         }
@@ -619,7 +623,7 @@ void LayoutTableSection::distributeRowSpanHeightToRows(SpanningLayoutTableCells&
         }
 
         // Below we are handling only row(s) who have at least one visible cell without rowspan value.
-        int totalPercent = 0;
+        LayoutUnit totalPercent = 0;
         int totalAutoRowsHeight = 0;
         int totalRemainingRowsHeight = spanningRowsHeight.totalRowsHeight;