reimplemented cell map in terms of nsVoidArrays for incremental building.

the cellmap is now built incrementally, driven by nsTableRowFrame::InitialReflow


git-svn-id: svn://10.0.0.236/trunk@8888 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/layout/html/table/src/celldata.h

@@ -33,6 +33,10 @@ class nsTableCellFrame;
 class CellData
 {
 public:
+  /** if not null, the cell that this CellData maps.
+    * if null, mRealCell points to the CellData that holds the 
+	* mapped cell frame.
+	*/
   nsTableCellFrame *mCell;
   CellData *mRealCell;
   CellData *mOverlap;