src: add InternalCallbackScope util constructor

Add an utility constructor for `AsyncWrap` classes that wish to
leverage `InternalCallbackScope`s.

PR-URL: nodejs/node#16461
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>

Author: addaleax

src/node.cc

@@ -1400,6 +1400,12 @@ CallbackScope::~CallbackScope() {
   delete private_;
 }
 
+InternalCallbackScope::InternalCallbackScope(AsyncWrap* async_wrap)
+    : InternalCallbackScope(async_wrap->env(),
+                            async_wrap->object(),
+                            { async_wrap->get_async_id(),
+                              async_wrap->get_trigger_async_id() }) {}
+
 InternalCallbackScope::InternalCallbackScope(Environment* env,
                                              Local<Object> object,
                                              const async_context& asyncContext,

src/node_internals.h

@@ -307,6 +307,8 @@ class InternalCallbackScope {
                         v8::Local<v8::Object> object,
                         const async_context& asyncContext,
                         ResourceExpectation expect = kRequireResource);
+  // Utility that can be used by AsyncWrap classes.
+  explicit InternalCallbackScope(AsyncWrap* async_wrap);
   ~InternalCallbackScope();
   void Close();