[CSS Grid Layout] Introduce an explicit type for resolved grid positions

Source/core/css/CSSGridTemplateAreasValue.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 34 matching lines @@
     ASSERT(m_columnCount);
 }
 
 static String stringForPosition(const NamedGridAreaMap& gridAreaMap, size_t row, size_t column)
 {
     Vector<String> candidates;
 
     NamedGridAreaMap::const_iterator end = gridAreaMap.end();
     for (NamedGridAreaMap::const_iterator it = gridAreaMap.begin(); it != end; ++it) {
         const GridCoordinate& coordinate = it->value;
-        if (row >= coordinate.rows.initialPositionIndex && row <= coordinate.rows.finalPositionIndex)
+        if (row >= coordinate.rows.resolvedInitialPosition.toInt() && row <= coordinate.rows.resolvedFinalPosition.toInt())
             candidates.append(it->key);
     }
 
     end = gridAreaMap.end();
     for (NamedGridAreaMap::const_iterator it = gridAreaMap.begin(); it != end; ++it) {
         const GridCoordinate& coordinate = it->value;
-        if (column >= coordinate.columns.initialPositionIndex && column <= coordinate.columns.finalPositionIndex && candidates.contains(it->key))
+        if (column >= coordinate.columns.resolvedInitialPosition.toInt() && column <= coordinate.columns.resolvedFinalPosition.toInt() && candidates.contains(it->key))
             return it->key;
     }
 
     return ".";
 }
 
 String CSSGridTemplateAreasValue::customCSSText() const
 {
     StringBuilder builder;
     for (size_t row = 0; row < m_rowCount; ++row) {
         builder.append('\"');
         for (size_t column = 0; column < m_columnCount; ++column) {
             builder.append(stringForPosition(m_gridAreaMap, row, column));
             if (column != m_columnCount - 1)
                 builder.append(' ');
         }
         builder.append('\"');
         if (row != m_rowCount - 1)
             builder.append(' ');
     }
     return builder.toString();
 }
 
 } // namespace WebCore