Add infrastructure for partial layouts

Source/core/rendering/RenderGrid.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 74 matching lines @@
     void placeItemsOnGrid();
     void populateExplicitGridAndOrderIterator();
     void placeSpecifiedMajorAxisItemsOnGrid(Vector<RenderBox*>);
     void placeAutoMajorAxisItemsOnGrid(Vector<RenderBox*>);
     void placeAutoMajorAxisItemOnGrid(RenderBox*);
     TrackSizingDirection autoPlacementMajorAxisDirection() const;
     TrackSizingDirection autoPlacementMinorAxisDirection() const;
 
     void layoutGridItems();
 
+    virtual bool supportsPartialLayout() const OVERRIDE { return false; }
+
     typedef LayoutUnit (RenderGrid::* SizingFunction)(RenderBox*, TrackSizingDirection, Vector<GridTrack>&);
     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);
 
     double computeNormalizedFractionBreadth(Vector<GridTrack>&, TrackSizingDirection, LayoutUnit availableLogicalSpace) const;
 
     const GridTrackSize& gridTrackSize(TrackSizingDirection, size_t) const;
@@ skipping 56 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderGrid());
     return static_cast<const RenderGrid*>(object);
 }
 
 // Catch unneeded cast.
 void toRenderGrid(const RenderGrid*);
 
 } // namespace WebCore
 
 #endif // RenderGrid_h