[CSS Grid Layout] Implementation of the grid-template shorthand.

Source/core/css/CSSParserValues.h

Index: Source/core/css/CSSParserValues.h
diff --git a/Source/core/css/CSSParserValues.h b/Source/core/css/CSSParserValues.h
index 37d56aac75202f6815ea7697921650889b626eb1..df20bed9a7d227a8efe7a9ae58e2dd6b68377061 100644
--- a/Source/core/css/CSSParserValues.h
+++ b/Source/core/css/CSSParserValues.h
@@ -189,6 +189,12 @@ public:
         --m_current;
         return current();
     }
+    void setCurrentIndex(unsigned index)
+    {
+        ASSERT(index >= 0 && index < m_values.size());
+        if (index >= 0 && index < m_values.size())
+            m_current = index;
+    }
 
     CSSParserValue* valueAt(unsigned i) { return i < m_values.size() ? &m_values[i] : 0; }