src: use existing strings over creating new ones

This is a very very minor change.

PR-URL: #14587
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

src/tcp_wrap.cc

@@ -55,13 +55,9 @@ void TCPWrap::Initialize(Local<Object> target,
   // Init properties
   t->InstanceTemplate()->Set(String::NewFromUtf8(env->isolate(), "reading"),
                              Boolean::New(env->isolate(), false));
-  t->InstanceTemplate()->Set(String::NewFromUtf8(env->isolate(), "owner"),
-                             Null(env->isolate()));
-  t->InstanceTemplate()->Set(String::NewFromUtf8(env->isolate(), "onread"),
-                             Null(env->isolate()));
-  t->InstanceTemplate()->Set(String::NewFromUtf8(env->isolate(),
-                                                 "onconnection"),
-                             Null(env->isolate()));
+  t->InstanceTemplate()->Set(env->owner_string(), Null(env->isolate()));
+  t->InstanceTemplate()->Set(env->onread_string(), Null(env->isolate()));
+  t->InstanceTemplate()->Set(env->onconnection_string(), Null(env->isolate()));
 
 
   env->SetProtoMethod(t, "close", HandleWrap::Close);