Fix handling of 'inherit' and 'initial' for grid lines

Source/core/rendering/style/StyleGridItemData.cpp

 /*
  * Copyright (C) 2012 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 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "config.h"
 #include "core/rendering/style/StyleGridItemData.h"
 
 #include "core/rendering/style/RenderStyle.h"
 
 namespace WebCore {
 
 StyleGridItemData::StyleGridItemData()
-    : m_gridStart(RenderStyle::initialGridPosition())
-    , m_gridEnd(RenderStyle::initialGridPosition())
-    , m_gridBefore(RenderStyle::initialGridPosition())
-    , m_gridAfter(RenderStyle::initialGridPosition())
+    : m_gridStart(RenderStyle::initialGridStart())
+    , m_gridEnd(RenderStyle::initialGridEnd())
+    , m_gridBefore(RenderStyle::initialGridBefore())
+    , m_gridAfter(RenderStyle::initialGridAfter())
 {
 }
 
 StyleGridItemData::StyleGridItemData(const StyleGridItemData& o)
     : RefCounted<StyleGridItemData>()
     , m_gridStart(o.m_gridStart)
     , m_gridEnd(o.m_gridEnd)
     , m_gridBefore(o.m_gridBefore)
     , m_gridAfter(o.m_gridAfter)
 {
 }
 
 } // namespace WebCore