[ast] Simplify NewBoilerplateDescription.

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index d56ef0fbfeb8bf43457d31537ec62922709a12eb..bb6b8f39d935ffc9fbcb7854e3286bbf5f192d2d 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -603,9 +603,9 @@ void ObjectLiteral::BuildConstantProperties(Isolate* isolate) {
   }
 
   Handle<BoilerplateDescription> constant_properties =
-      isolate->factory()->NewBoilerplateDescription(
-          boilerplate_properties_, properties()->length() - index_keys,
-          has_seen_proto);
+      isolate->factory()->NewBoilerplateDescription(boilerplate_properties_,
+                                                    properties()->length(),
+                                                    index_keys, has_seen_proto);
 
   int position = 0;
   for (int i = 0; i < properties()->length(); i++) {