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

Source/core/css/parser/CSSPropertyParser.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 3692 matching lines @@
             }
 
             NamedGridAreaMap::iterator gridAreaIt = gridAreaMap.find(gridAreaName);
             if (gridAreaIt == gridAreaMap.end()) {
                 gridAreaMap.add(gridAreaName, GridCoordinate(GridSpan(rowCount, rowCount), GridSpan(currentCol, lookAheadCol)));
             } else {
                 GridCoordinate& gridCoordinate = gridAreaIt->value;
 
                 // The following checks test that the grid area is a single filled-in rectangle.
                 // 1. The new row is adjacent to the previously parsed row.
-                if (rowCount != gridCoordinate.rows.initialPositionIndex + 1)
+                if (rowCount != gridCoordinate.rows.resolvedInitialPosition.next())
                     return nullptr;
 
                 // 2. The new area starts at the same position as the previously parsed area.
-                if (currentCol != gridCoordinate.columns.initialPositionIndex)
+                if (currentCol != gridCoordinate.columns.resolvedInitialPosition)
                     return nullptr;
 
                 // 3. The new area ends at the same position as the previously parsed area.
-                if (lookAheadCol != gridCoordinate.columns.finalPositionIndex)
+                if (lookAheadCol != gridCoordinate.columns.resolvedFinalPosition)
                     return nullptr;
 
-                ++gridCoordinate.rows.finalPositionIndex;
+                ++gridCoordinate.rows.resolvedFinalPosition;
             }
             currentCol = lookAheadCol;
         }
 
         ++rowCount;
         m_valueList->next();
     }
 
     if (!rowCount || !columnCount)
         return nullptr;
@@ skipping 4721 matching lines @@
         parsedValues->append(CSSPrimitiveValue::createIdentifier(CSSValueFill));
     if (!seenStroke)
         parsedValues->append(CSSPrimitiveValue::createIdentifier(CSSValueStroke));
     if (!seenMarkers)
         parsedValues->append(CSSPrimitiveValue::createIdentifier(CSSValueMarkers));
 
     return parsedValues.release();
 }
 
 } // namespace WebCore