[CSS Grid Layout] Store m_grid across layout

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 604 matching lines @@
 
     void paintRootBoxFillLayers(const PaintInfo&);
 
     RenderObject* splitAnonymousBoxesAroundChild(RenderObject* beforeChild);
 
     virtual void addLayerHitTestRects(LayerHitTestRects&, const RenderLayer* currentCompositedLayer, const LayoutPoint& layerOffset) const OVERRIDE;
     virtual void computeSelfHitTestRects(Vector<LayoutRect>&, const LayoutPoint& layerOffset) const OVERRIDE;
 
 private:
     void updateShapeOutsideInfoAfterStyleChange(const ShapeValue* shapeOutside, const ShapeValue* oldShapeOutside);
+    void updateGridPositionAfterStyleChange(const RenderStyle*);
 
     bool includeVerticalScrollbarSize() const;
     bool includeHorizontalScrollbarSize() const;
 
     // Returns true if we did a full repaint
     bool repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer* layers, bool drawingBackground);
 
     bool skipContainingBlockForPercentHeightCalculation(const RenderBox* containingBlock) const;
 
     LayoutUnit containingBlockLogicalWidthForPositioned(const RenderBoxModelObject* containingBlock, RenderRegion* = 0,
@@ skipping 107 matching lines @@
         if (UNLIKELY(m_inlineBoxWrapper != 0))
             deleteLineBoxWrapper();
     }
 
     m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace WebCore
 
 #endif // RenderBox_h