[CSS Grid Layout] Fix auto-placement algorithm

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 914 matching lines @@
             // This will happen when we have "span <custom-indent>", which has a different resolution based on the position.
             GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *gridItem, autoPlacementMajorAxisDirection(), majorAxisIndex);
             emptyGridArea = findEmptyGridAreaAtSpecifiedPositionsInsideGrid(gridItem, autoPlacementMajorAxisDirection(), majorAxisPositions);
 
             if (emptyGridArea) {
                 // Check that it fits in the minor axis direction, as we shouldn't grow in that direction here (it was already managed in populateExplicitGridAndOrderIterator()).
                 GridResolvedPosition minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.resolvedFinalPosition : emptyGridArea->rows.resolvedFinalPosition;
                 const size_t endOfMinorAxis = autoPlacementMinorAxisDirection() == ForColumns ? gridColumnCount() : gridRowCount();
                 if (minorAxisFinalPositionIndex.toInt() < endOfMinorAxis)
                     break;
+
+                // Discard empty grid area as it does not fit in the minor axis direction.
+                // We don't need to create a new empty grid area yet as we might find a valid one in the next iteration.
+                emptyGridArea = nullptr;
             }
         }
 
         if (!emptyGridArea) {
             GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *gridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
             emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), minorAxisPositions);
         }
     }
 
     insertItemIntoGrid(gridItem, *emptyGridArea);
@@ skipping 314 matching lines @@
     if (isOutOfFlowPositioned())
         return "RenderGrid (positioned)";
     if (isAnonymous())
         return "RenderGrid (generated)";
     if (isRelPositioned())
         return "RenderGrid (relative positioned)";
     return "RenderGrid";
 }
 
 } // namespace WebCore