Combine and simplify LayoutTableSection::DirtiedRows() and DirtiedEffectiveColumns()

third_party/WebKit/Source/core/paint/TableRowPainter.cpp

Index: third_party/WebKit/Source/core/paint/TableRowPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/TableRowPainter.cpp b/third_party/WebKit/Source/core/paint/TableRowPainter.cpp
index 700a2e8e96be7a8fcb1fd8ba17fd0ea5c57e63d1..3edfcc566c388e8f4715e1d8d549fc0f96132e8a 100644
--- a/third_party/WebKit/Source/core/paint/TableRowPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/TableRowPainter.cpp
@@ -32,8 +32,10 @@ void TableRowPainter::Paint(const PaintInfo& paint_info,
     cull_rect.MoveBy(layout_table_row_.PhysicalLocation(section));
     LayoutRect logical_rect_in_section =
         section->LogicalRectForWritingModeAndDirection(cull_rect);
-    CellSpan dirtied_columns =
-        section->DirtiedEffectiveColumns(logical_rect_in_section);
+    CellSpan dirtied_rows;
+    CellSpan dirtied_columns;
+    section->DirtiedRowsAndEffectiveColumns(logical_rect_in_section,
+                                            dirtied_rows, dirtied_columns);

[wkorman, 2017/05/16 20:30:11]

If we passed pointers rather than refs, could pass nullptr for dirtied_rows and
then skip computation. Assume computation is pretty cheap but maybe for huge
tables could be useful. Just a thought while reading.

[Xianzhu, 2017/05/17 00:33:21]

This is the only case that only one output is needed, and the case is rare
(table row has self-painting layer). Even if the caller only wants one, the
function itself still needs to compute both in some cases.

     PaintBoxDecorationBackground(paint_info, paint_offset, dirtied_columns);
   }
 
@@ -96,7 +98,7 @@ void TableRowPainter::PaintBoxDecorationBackground(
 
   if (has_background) {
     PaintInfo paint_info_for_cells = paint_info.ForDescendants();
-    for (auto c = dirtied_columns.Start(); c < dirtied_columns.end(); c++) {
+    for (auto c = dirtied_columns.Start(); c < dirtied_columns.End(); c++) {
       if (const auto* cell =
               section->OriginatingCellAt(layout_table_row_.RowIndex(), c))
         PaintBackgroundBehindCell(*cell, paint_info_for_cells, paint_offset);