Move GridCoordinate and GridSpan to a separate file

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 e51c478e6bad80369ddf4ee938189815325ad016..074f8597bb85d60d552590662bb2605f4d1805aa 100644
--- a/Source/core/rendering/RenderGrid.h
+++ b/Source/core/rendering/RenderGrid.h
@@ -30,6 +30,8 @@
 
 namespace WebCore {
 
+class GridCoordinate;
+class GridSpan;
 class GridTrack;
 
 enum GridPositionSide {
@@ -58,41 +60,6 @@ private:
 
     LayoutUnit computePreferredTrackWidth(const GridLength&, size_t) const;
 
-    struct GridSpan {
-        static PassOwnPtr<GridSpan> create(size_t initialPosition, size_t finalPosition)
-        {
-            return adoptPtr(new GridSpan(initialPosition, finalPosition));
-        }
-
-        GridSpan(size_t initialPosition, size_t finalPosition)
-            : initialPositionIndex(initialPosition)
-            , finalPositionIndex(finalPosition)
-        {
-            ASSERT(initialPositionIndex <= finalPositionIndex);
-        }
-
-        size_t initialPositionIndex;
-        size_t finalPositionIndex;
-    };
-
-    struct GridCoordinate {
-        // HashMap requires a default constuctor.
-        GridCoordinate()
-            : columns(0, 0)
-            , rows(0, 0)
-        {
-        }
-
-        GridCoordinate(const GridSpan& r, const GridSpan& c)
-            : columns(c)
-            , rows(r)
-        {
-        }
-
-        GridSpan columns;
-        GridSpan rows;
-    };
-
     class GridIterator;
     enum TrackSizingDirection { ForColumns, ForRows };
     void computedUsedBreadthOfGridTracks(TrackSizingDirection, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks);