[CSS Grid Layout] Rename grid placement properties

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 15 matching lines @@
 #ifndef RenderGrid_h
 #define RenderGrid_h
 
 #include "core/rendering/RenderBlock.h"
 
 namespace WebCore {
 
 class GridTrack;
 
 enum GridPositionSide {
-    StartSide,
-    EndSide,
-    BeforeSide,
-    AfterSide
+    ColumnStartSide,
+    ColumnEndSide,
+    RowStartSide,
+    RowEndSide
 };
 
 class RenderGrid FINAL : public RenderBlock {
 public:
     RenderGrid(Element*);
     virtual ~RenderGrid();
 
     virtual const char* renderName() const OVERRIDE;
 
     virtual void layoutBlock(bool relayoutChildren, LayoutUnit pageLogicalHeight = 0) OVERRIDE;
@@ skipping 109 matching lines @@
         return m_grid.size();
     }
 
     Vector<Vector<Vector<RenderBox*, 1> > > m_grid;
     HashMap<const RenderBox*, GridCoordinate> m_gridItemCoordinate;
 };
 
 } // namespace WebCore
 
 #endif // RenderGrid_h