[parser] Delete has_seen_proto in ObjectLiteral.

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index 02e915c15df62a5d8d6022b5ce1b65a23c0b84d1..542f0a3bf504cbf996b3ae8bac55a3304c2ba391 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -595,8 +595,7 @@ class PreParserFactory {
   }
   PreParserExpression NewObjectLiteral(PreParserExpressionList properties,
                                        int literal_index,
-                                       int boilerplate_properties,
-                                       bool has_seen_proto, int pos,
+                                       int boilerplate_properties, int pos,
                                        bool has_rest_property) {
     return PreParserExpression::ObjectLiteral(properties.variables_);
   }