[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;

[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 };
@@ -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;
 };