Fix for bug #21703. r=karnaze, a=chofmann

layout/html/table/src/nsTableRowGroupFrame.cpp

@@ -597,10 +597,12 @@ void nsTableRowGroupFrame::CalculateRowHeights(nsIPresContext* aPresContext,
   PRBool  hasRowSpanningCell = PR_FALSE;
   PRInt32 numRows;
   GetRowCount(numRows, PR_FALSE);
-  if (numRows <= 0) return;
-  nscoord *rowHeights = new nscoord[numRows];
+  nscoord* rowHeights = nsnull;
+  if (numRows > 0) {
+    rowHeights = new nscoord[numRows];
     if (!rowHeights) return;
     nsCRT::memset (rowHeights, 0, numRows*sizeof(nscoord));
+  }
 
   /* Step 1:  get the height of the tallest cell in the row and save it for
    *          pass 2. This height is for table cells that originate in this

layout/tables/nsTableRowGroupFrame.cpp

@@ -597,10 +597,12 @@ void nsTableRowGroupFrame::CalculateRowHeights(nsIPresContext* aPresContext,
   PRBool  hasRowSpanningCell = PR_FALSE;
   PRInt32 numRows;
   GetRowCount(numRows, PR_FALSE);
-  if (numRows <= 0) return;
-  nscoord *rowHeights = new nscoord[numRows];
+  nscoord* rowHeights = nsnull;
+  if (numRows > 0) {
+    rowHeights = new nscoord[numRows];
     if (!rowHeights) return;
     nsCRT::memset (rowHeights, 0, numRows*sizeof(nscoord));
+  }
 
   /* Step 1:  get the height of the tallest cell in the row and save it for
    *          pass 2. This height is for table cells that originate in this