Allow defining named grid lines on the grid element

Source/core/rendering/style/StyleGridData.h

Index: Source/core/rendering/style/StyleGridData.h
diff --git a/Source/core/rendering/style/StyleGridData.h b/Source/core/rendering/style/StyleGridData.h
index d2382b959239f4f58f6f7b7be6ac0cf3e5a9c0d8..4ff9175a7377fbbf5d01d86a427b6d7eef68d5cc 100644
--- a/Source/core/rendering/style/StyleGridData.h
+++ b/Source/core/rendering/style/StyleGridData.h
@@ -31,9 +31,12 @@
 #include <wtf/PassRefPtr.h>
 #include <wtf/RefCounted.h>
 #include <wtf/Vector.h>
+#include <wtf/text/WTFString.h>
 
 namespace WebCore {
 
+typedef HashMap<String, Vector<size_t> > NamedGridLinesMap;
+
 class StyleGridData : public RefCounted<StyleGridData> {
 public:
     static PassRefPtr<StyleGridData> create() { return adoptRef(new StyleGridData); }
@@ -41,7 +44,7 @@ public:
 
     bool operator==(const StyleGridData& o) const
     {
-        return m_gridColumns == o.m_gridColumns && m_gridRows == o.m_gridRows && m_gridAutoFlow == o.m_gridAutoFlow && m_gridAutoRows == o.m_gridAutoRows && m_gridAutoColumns == o.m_gridAutoColumns;
+        return m_gridColumns == o.m_gridColumns && m_gridRows == o.m_gridRows && m_gridAutoFlow == o.m_gridAutoFlow && m_gridAutoRows == o.m_gridAutoRows && m_gridAutoColumns == o.m_gridAutoColumns && m_namedGridColumnLines == o.m_namedGridColumnLines && m_namedGridRowLines == o.m_namedGridRowLines;
     }
 
     bool operator!=(const StyleGridData& o) const
@@ -53,6 +56,9 @@ public:
     Vector<GridTrackSize> m_gridColumns;
     Vector<GridTrackSize> m_gridRows;
 
+    NamedGridLinesMap m_namedGridColumnLines;
+    NamedGridLinesMap m_namedGridRowLines;
+
     GridAutoFlow m_gridAutoFlow;
 
     GridTrackSize m_gridAutoRows;