[CSS Grid Layout] Content Distribution support for grid.

Source/core/layout/LayoutGrid.h

Index: Source/core/layout/LayoutGrid.h
diff --git a/Source/core/layout/LayoutGrid.h b/Source/core/layout/LayoutGrid.h
index d138a24722d7461a46b9421abe5935f6d20836f6..5fa527183bc266a6d223782f1ecb08ef7b861497 100644
--- a/Source/core/layout/LayoutGrid.h
+++ b/Source/core/layout/LayoutGrid.h
@@ -124,9 +124,9 @@ private:
     LayoutUnit endOfRowForChild(const LayoutBox& child) const;
     LayoutUnit centeredRowPositionForChild(const LayoutBox&) const;
     LayoutUnit rowPositionForChild(const LayoutBox&) const;
-    LayoutUnit contentPositionAndDistributionColumnOffset(LayoutUnit availableFreeSpace, ContentPosition, ContentDistributionType, OverflowAlignment, unsigned numberOfItems) const;
-    LayoutUnit contentPositionAndDistributionRowOffset(LayoutUnit availableFreeSpace, ContentPosition, ContentDistributionType, OverflowAlignment, unsigned numberOfItems) const;
-    LayoutPoint findChildLogicalPosition(const LayoutBox&, LayoutSize contentAlignmentOffset) const;
+    void computeContentPositionAndDistributionRowOffset(LayoutUnit availableFreeSpace, GridSizingData&) const;
+    void computeContentPositionAndDistributionColumnOffset(LayoutUnit availableFreeSpace, GridSizingData&) const;
+    LayoutPoint findChildLogicalPosition(const LayoutBox&, GridSizingData&) const;
     GridCoordinate cachedGridCoordinate(const LayoutBox&) const;
 
     LayoutUnit gridAreaBreadthForChild(const LayoutBox& child, GridTrackSizingDirection, const Vector<GridTrack>&) const;