[css-grid] Initial support for implicit grid before explicit grid

third_party/WebKit/Source/core/layout/LayoutGrid.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 195 matching lines @@
     bool m_gridIsDirty;
     Vector<LayoutUnit> m_rowPositions;
     Vector<LayoutUnit> m_columnPositions;
     HashMap<const LayoutBox*, GridCoordinate> m_gridItemCoordinate;
     OrderIterator m_orderIterator;
     Vector<LayoutBox*> m_gridItemsOverflowingGridArea;
     HashMap<const LayoutBox*, size_t> m_gridItemsIndexesMap;
 
     LayoutUnit m_minContentHeight { -1 };
     LayoutUnit m_maxContentHeight { -1 };
+
+    int m_smallestRowStart;
+    int m_smallestColumnStart;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutGrid, isLayoutGrid());
 
 } // namespace blink
 
 #endif // LayoutGrid_h