[CSS Grid Layout] Implementation of the align-self property in grid.

Source/core/rendering/RenderGrid.h

Index: Source/core/rendering/RenderGrid.h
diff --git a/Source/core/rendering/RenderGrid.h b/Source/core/rendering/RenderGrid.h
index f1f2fa1835c0f480f54b6b27d5bd36ecab090e78..e714b0eda061b7c29bea78d4761d857a1ba871d4 100644
--- a/Source/core/rendering/RenderGrid.h
+++ b/Source/core/rendering/RenderGrid.h
@@ -110,6 +110,9 @@ private:
     LayoutUnit columnPositionAlignedWithGridContainerEnd(const RenderBox*) const;
     LayoutUnit centeredColumnPositionForChild(const RenderBox*) const;
     LayoutUnit columnPositionForChild(const RenderBox*) const;
+    LayoutUnit startOfRowForChild(const RenderBox* child) const;
+    LayoutUnit endOfRowForChild(const RenderBox* child) const;
+    LayoutUnit centeredRowPositionForChild(const RenderBox*) const;
     LayoutUnit rowPositionForChild(const RenderBox*) const;
     LayoutPoint findChildLogicalPosition(const RenderBox*) const;
     GridCoordinate cachedGridCoordinate(const RenderBox*) const;