[css-grid] Fix crash when using auto repeat for indefinite widths

third_party/WebKit/Source/core/layout/LayoutGrid.h

Index: third_party/WebKit/Source/core/layout/LayoutGrid.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutGrid.h b/third_party/WebKit/Source/core/layout/LayoutGrid.h
index 2b7f531231f44fba6c4270a07ab86968c9e71a77..7ff88ffb9e9a53f14d40e04e8ab8824522b134ef 100644
--- a/third_party/WebKit/Source/core/layout/LayoutGrid.h
+++ b/third_party/WebKit/Source/core/layout/LayoutGrid.h
@@ -131,7 +131,7 @@ private:
 
     size_t computeAutoRepeatTracksCount(GridTrackSizingDirection) const;
 
-    void placeItemsOnGrid();
+    void placeItemsOnGrid(SizingOperation);
     void populateExplicitGridAndOrderIterator();
     std::unique_ptr<GridArea> createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(const LayoutBox&, GridTrackSizingDirection, const GridSpan& specifiedPositions) const;
     void placeSpecifiedMajorAxisItemsOnGrid(const Vector<LayoutBox*>&);
@@ -209,17 +209,19 @@ private:
     bool isOrthogonalChild(const LayoutBox&) const;
     GridTrackSizingDirection flowAwareDirectionForChild(const LayoutBox&, GridTrackSizingDirection) const;
 
+    void clearGridDataAndMarkAsDirty() const;
+
     typedef Vector<Vector<GridCell>> GridRepresentation;
-    GridRepresentation m_grid;
-    bool m_gridIsDirty;
+    mutable GridRepresentation m_grid;
+    mutable bool m_gridIsDirty;
     Vector<LayoutUnit> m_rowPositions;
     Vector<LayoutUnit> m_columnPositions;
     LayoutUnit m_offsetBetweenColumns;
     LayoutUnit m_offsetBetweenRows;
-    HashMap<const LayoutBox*, GridArea> m_gridItemArea;
+    mutable HashMap<const LayoutBox*, GridArea> m_gridItemArea;
     OrderIterator m_orderIterator;
-    Vector<LayoutBox*> m_gridItemsOverflowingGridArea;
-    HashMap<const LayoutBox*, size_t> m_gridItemsIndexesMap;
+    mutable Vector<LayoutBox*> m_gridItemsOverflowingGridArea;
+    mutable HashMap<const LayoutBox*, size_t> m_gridItemsIndexesMap;
 
     LayoutUnit m_minContentHeight { -1 };
     LayoutUnit m_maxContentHeight { -1 };
@@ -227,8 +229,8 @@ private:
     int m_smallestRowStart;
     int m_smallestColumnStart;
 
-    size_t m_autoRepeatColumns { 0 };
-    size_t m_autoRepeatRows { 0 };
+    mutable size_t m_autoRepeatColumns { 0 };
+    mutable size_t m_autoRepeatRows { 0 };
 
     bool m_hasAnyOrthogonalChild;
 };