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

Source/core/rendering/RenderGrid.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 92 matching lines @@
 
     LayoutUnit logicalHeightForChild(RenderBox*, Vector<GridTrack>&);
     LayoutUnit minContentForChild(RenderBox*, GridTrackSizingDirection, Vector<GridTrack>& columnTracks);
     LayoutUnit maxContentForChild(RenderBox*, GridTrackSizingDirection, Vector<GridTrack>& columnTracks);
     LayoutUnit startOfColumnForChild(const RenderBox* child) const;
     LayoutUnit endOfColumnForChild(const RenderBox* child) const;
     LayoutUnit columnPositionAlignedWithGridContainerStart(const RenderBox*) const;
     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;
 
     LayoutUnit gridAreaBreadthForChild(const RenderBox* child, GridTrackSizingDirection, const Vector<GridTrack>&) const;
 
     virtual void paintChildren(PaintInfo&, const LayoutPoint&) OVERRIDE;
 
     bool gridIsDirty() const { return m_gridIsDirty; }
 
@@ skipping 23 matching lines @@
     Vector<RenderBox*> m_gridItemsOverflowingGridArea;
 
     friend class GridCoordinateSorter;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderGrid, isRenderGrid());
 
 } // namespace WebCore
 
 #endif // RenderGrid_h