src: remove unused Worker::child_port_ member

This fixes a compiler warning introduced in 9225939.

PR-URL: #31599
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

src/node_worker.cc

@@ -253,14 +253,6 @@ void Worker::Run() {
       Isolate::DisallowJavascriptExecutionScope disallow_js(isolate_,
           Isolate::DisallowJavascriptExecutionScope::THROW_ON_FAILURE);
 
-      // Grab the parent-to-child channel and render is unusable.
-      MessagePort* child_port;
-      {
-        Mutex::ScopedLock lock(mutex_);
-        child_port = child_port_;
-        child_port_ = nullptr;
-      }
-
       {
         Context::Scope context_scope(env_->context());
         {
@@ -396,13 +388,13 @@ void Worker::CreateEnvMessagePort(Environment* env) {
   HandleScope handle_scope(isolate_);
   Mutex::ScopedLock lock(mutex_);
   // Set up the message channel for receiving messages in the child.
-  child_port_ = MessagePort::New(env,
-                                 env->context(),
-                                 std::move(child_port_data_));
+  MessagePort* child_port = MessagePort::New(env,
+                                             env->context(),
+                                             std::move(child_port_data_));
   // MessagePort::New() may return nullptr if execution is terminated
   // within it.
-  if (child_port_ != nullptr)
-    env->set_message_port(child_port_->object(isolate_));
+  if (child_port != nullptr)
+    env->set_message_port(child_port->object(isolate_));
 }
 
 void Worker::JoinThread() {

src/node_worker.h

@@ -102,9 +102,6 @@ class Worker : public AsyncWrap {
   std::unique_ptr<MessagePortData> child_port_data_;
   std::shared_ptr<KVStore> env_vars_;
 
-  // The child port is kept alive by the child Environment's persistent
-  // handle to it, as long as that child Environment exists.
-  MessagePort* child_port_ = nullptr;
   // This is always kept alive because the JS object associated with the Worker
   // instance refers to it via its [kPort] property.
   MessagePort* parent_port_ = nullptr;