[CSS Grid Layout] Avoid preferred logical widths' recomputations

Source/core/rendering/RenderGrid.cpp

 /*
  * 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 577 matching lines @@
     Vector<GridTrack*> tracks;
     for (size_t trackIndex = initialTrackIndex; trackIndex <= finalTrackIndex; ++trackIndex) {
         const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
         if (!(trackSize.*filterFunction)())
             continue;
 
         GridTrack& track = (direction == ForColumns) ? columnTracks[trackIndex] : rowTracks[trackIndex];
         tracks.append(&track);
     }
 
+    if (tracks.isEmpty())
+        return;
+
     LayoutUnit additionalBreadthSpace = (this->*sizingFunction)(gridItem, direction, columnTracks);
     for (size_t trackIndexForSpace = initialTrackIndex; trackIndexForSpace <= finalTrackIndex; ++trackIndexForSpace) {
         GridTrack& track = (direction == ForColumns) ? columnTracks[trackIndexForSpace] : rowTracks[trackIndexForSpace];
         additionalBreadthSpace -= (track.*trackGetter)();
     }
 
     // FIXME: We should pass different values for |tracksForGrowthAboveMaxBreadth|.
     distributeSpaceToTracks(tracks, &tracks, trackGetter, trackGrowthFunction, additionalBreadthSpace);
 }
 
@@ skipping 528 matching lines @@
     if (isOutOfFlowPositioned())
         return "RenderGrid (positioned)";
     if (isAnonymous())
         return "RenderGrid (generated)";
     if (isRelPositioned())
         return "RenderGrid (relative positioned)";
     return "RenderGrid";
 }
 
 } // namespace WebCore