[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 fbde0b77ec24bb061aefc7c779e1230257194440..12974460307b28e1de3263159f3b00efc88f8dc1 100644
--- a/Source/core/css/CSSParserValues.h
+++ b/Source/core/css/CSSParserValues.h
@@ -191,6 +191,12 @@ public:
         --m_current;
         return current();
     }
+    void setCurrentIndex(unsigned index)
+    {
+        ASSERT(index < m_values.size());
+        if (index < m_values.size())
+            m_current = index;
+    }
 
     CSSParserValue* valueAt(unsigned i) { return i < m_values.size() ? &m_values[i] : 0; }