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

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 113 matching lines @@
     void computeUsedBreadthOfGridTracks(GridTrackSizingDirection, GridSizingData&, LayoutUnit& baseSizesWithoutMaximization, LayoutUnit& growthLimitsWithoutMaximization);
     LayoutUnit computeUsedBreadthOfMinLength(const GridLength&, LayoutUnit maxBreadth) const;
     LayoutUnit computeUsedBreadthOfMaxLength(const GridLength&, LayoutUnit usedBreadth, LayoutUnit maxBreadth) const;
     void resolveContentBasedTrackSizingFunctions(GridTrackSizingDirection, GridSizingData&);
 
     void ensureGridSize(size_t maximumRowSize, size_t maximumColumnSize);
     void insertItemIntoGrid(LayoutBox&, const GridArea&);
 
     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*>&);
     void placeAutoMajorAxisItemsOnGrid(const Vector<LayoutBox*>&);
     void placeAutoMajorAxisItemOnGrid(LayoutBox&, std::pair<size_t, size_t>& autoPlacementCursor);
     GridTrackSizingDirection autoPlacementMajorAxisDirection() const;
     GridTrackSizingDirection autoPlacementMinorAxisDirection() const;
 
     void computeIntrinsicLogicalHeight(GridSizingData&);
     LayoutUnit computeTrackBasedLogicalHeight(const GridSizingData&) const;
@@ skipping 57 matching lines @@
 
     size_t gridItemSpan(const LayoutBox&, GridTrackSizingDirection);
     bool spanningItemCrossesFlexibleSizedTracks(const GridSpan&, GridTrackSizingDirection, SizingOperation) const;
 
     size_t gridColumnCount() const;
     size_t gridRowCount() const;
 
     bool isOrthogonalChild(const LayoutBox&) const;
     GridTrackSizingDirection flowAwareDirectionForChild(const LayoutBox&, GridTrackSizingDirection) const;
 
+    void clearGridDataAndMarkAsDirty() const;

[jfernandez, 2016/07/11 12:52:22]

Why const ?

[svillar, 2016/07/11 14:18:43]

Because it's called inside computeIntrinsicLogicalWidths() which is a const
function. We're only modifying mutable attributes so it's technically correct,
although I agree that a const method called clear looks weird.

The actual problem is that we're using the track sizing algorithm (which
modifies some attributes of the layout object) to compute the intrinsic width,
something that should not do this kind of state modifications. That's the reason
why we have a couple of const_cast that should be indeed removed, but that is
another topic and should be addressed in some other bug IMHO.

+
     typedef Vector<Vector<GridCell>> GridRepresentation;
-    GridRepresentation m_grid;
-    bool m_gridIsDirty;
+    mutable GridRepresentation m_grid;

[eae, 2016/07/12 17:38:48]

A const clear method and mutable non-cache data members is a pretty big warning
flag that something is wrong with the API. We really need to find a better way
to do this.

+    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 };
 
     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;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutGrid, isLayoutGrid());
 
 } // namespace blink
 
 #endif // LayoutGrid_h