Add support for the column-fill property.

Source/core/css/CSSPrimitiveValueMappings.h

Index: Source/core/css/CSSPrimitiveValueMappings.h
diff --git a/Source/core/css/CSSPrimitiveValueMappings.h b/Source/core/css/CSSPrimitiveValueMappings.h
index 0de35fd03f46f325c0544306a83072050786a693..39d591aa1a2a6ea49f2cfa0289687668fdb56c43 100644
--- a/Source/core/css/CSSPrimitiveValueMappings.h
+++ b/Source/core/css/CSSPrimitiveValueMappings.h
@@ -176,6 +176,32 @@ template<> inline CSSPrimitiveValue::operator CSSReflectionDirection() const
     return ReflectionBelow;
 }
 
+template<> inline CSSPrimitiveValue::CSSPrimitiveValue(ColumnFill columnFill)
+    : CSSValue(PrimitiveClass)
+{
+    m_primitiveUnitType = CSS_VALUE_ID;
+    switch (columnFill) {
+    case ColumnFillAuto:
+        m_value.valueID = CSSValueAuto;
+        break;
+    case ColumnFillBalance:
+        m_value.valueID = CSSValueBalance;
+        break;
+    }
+}
+
+template<> inline CSSPrimitiveValue::operator ColumnFill() const
+{
+    if (m_primitiveUnitType == CSS_VALUE_ID) {
+        if (m_value.valueID == CSSValueBalance)
+            return ColumnFillBalance;
+        if (m_value.valueID == CSSValueAuto)
+            return ColumnFillAuto;
+    }
+    ASSERT_NOT_REACHED();
+    return ColumnFillBalance;
+}
+
 template<> inline CSSPrimitiveValue::CSSPrimitiveValue(ColumnSpan columnSpan)
     : CSSValue(PrimitiveClass)
 {