Cache several vectors to avoid malloc/free churn

Source/core/rendering/RenderGrid.h

Index: Source/core/rendering/RenderGrid.h
diff --git a/Source/core/rendering/RenderGrid.h b/Source/core/rendering/RenderGrid.h
index b3956718a6ab13ebb79d43254597d81e642c1d18..2f9ea1f1ffb0224ec5666d58adda286f37fa4915 100644
--- a/Source/core/rendering/RenderGrid.h
+++ b/Source/core/rendering/RenderGrid.h
@@ -72,12 +72,13 @@ private:
     LayoutUnit computePreferredTrackWidth(const GridLength&, size_t) const;
 
     class GridIterator;
+    class GridSizingData;
     enum TrackSizingDirection { ForColumns, ForRows };
-    void computedUsedBreadthOfGridTracks(TrackSizingDirection, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks);
+    void computedUsedBreadthOfGridTracks(TrackSizingDirection, GridSizingData&);
     LayoutUnit computeUsedBreadthOfMinLength(TrackSizingDirection, const GridLength&) const;
     LayoutUnit computeUsedBreadthOfMaxLength(TrackSizingDirection, const GridLength&, LayoutUnit usedBreadth) const;
     LayoutUnit computeUsedBreadthOfSpecifiedLength(TrackSizingDirection, const Length&) const;
-    void resolveContentBasedTrackSizingFunctions(TrackSizingDirection, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks, const Vector<size_t>&, LayoutUnit& availableLogicalSpace);
+    void resolveContentBasedTrackSizingFunctions(TrackSizingDirection, GridSizingData&, LayoutUnit& availableLogicalSpace);
 
     void growGrid(TrackSizingDirection);
     void insertItemIntoGrid(RenderBox*, size_t rowTrack, size_t columnTrack);
@@ -91,7 +92,7 @@ private:
     TrackSizingDirection autoPlacementMinorAxisDirection() const;
 
     void layoutGridItems();
-    void populateGridPositions(const Vector<GridTrack>& columnTracks, const Vector<GridTrack>& rowTracks);
+    void populateGridPositions(const GridSizingData&);
 
     virtual bool supportsPartialLayout() const OVERRIDE { return false; }
 
@@ -99,8 +100,8 @@ private:
     typedef LayoutUnit (GridTrack::* AccumulatorGetter)() const;
     typedef void (GridTrack::* AccumulatorGrowFunction)(LayoutUnit);
     typedef bool (GridTrackSize::* FilterFunction)() const;
-    void resolveContentBasedTrackSizingFunctionsForItems(TrackSizingDirection, Vector<GridTrack>& columnTracks, Vector<GridTrack>& rowTracks, RenderBox*, FilterFunction, SizingFunction, AccumulatorGetter, AccumulatorGrowFunction);
-    void distributeSpaceToTracks(Vector<GridTrack*>&, Vector<GridTrack*>* tracksForGrowthAboveMaxBreadth, AccumulatorGetter, AccumulatorGrowFunction, LayoutUnit& availableLogicalSpace);
+    void resolveContentBasedTrackSizingFunctionsForItems(TrackSizingDirection, GridSizingData&, RenderBox*, FilterFunction, SizingFunction, AccumulatorGetter, AccumulatorGrowFunction);
+    void distributeSpaceToTracks(Vector<GridTrack*>&, Vector<GridTrack*>* tracksForGrowthAboveMaxBreadth, AccumulatorGetter, AccumulatorGrowFunction, GridSizingData&, LayoutUnit& availableLogicalSpace);
 
     double computeNormalizedFractionBreadth(Vector<GridTrack>&, TrackSizingDirection, LayoutUnit availableLogicalSpace) const;
 
@@ -112,7 +113,7 @@ private:
     LayoutUnit logicalContentHeightForChild(RenderBox*, Vector<GridTrack>&);
     LayoutUnit minContentForChild(RenderBox*, TrackSizingDirection, Vector<GridTrack>& columnTracks);
     LayoutUnit maxContentForChild(RenderBox*, TrackSizingDirection, Vector<GridTrack>& columnTracks);
-    LayoutPoint findChildLogicalPosition(RenderBox*, const Vector<GridTrack>& columnTracks, const Vector<GridTrack>& rowTracks);
+    LayoutPoint findChildLogicalPosition(RenderBox*, const GridSizingData&);
     GridCoordinate cachedGridCoordinate(const RenderBox*) const;
 
     GridSpan resolveGridPositionsFromAutoPlacementPosition(const RenderBox*, TrackSizingDirection, size_t) const;