worker: enable passing command line flags

This PR adds the ability to provide Workers with their own
execArgv flags in replacement of the main thread's execArgv. Only
per-Isolate/per-Environment options are allowed. Per-Process options
and V8 flags are not allowed. Passing an empty execArgv array will
reset per-Isolate and per-Environment options of the Worker to their
defaults. If execArgv option is not passed, the Worker will get
the same flags as the main thread.

Usage example:
```
const worker = new Worker(__filename, {
    execArgv: ['--trace-warnings'],
});
```

PR-URL: https://github.com/nodejs/node/pull/25467
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/node_worker.h b/src/node_worker.h
index cbd4a86157..dd054ac38d 100644
--- a/src/node_worker.h
+++ b/src/node_worker.h
@@ -12,7 +12,10 @@ namespace worker {
 // A worker thread, as represented in its parent thread.
 class Worker : public AsyncWrap {
  public:
-  Worker(Environment* env, v8::Local<v8::Object> wrap, const std::string& url);
+  Worker(Environment* env,
+         v8::Local<v8::Object> wrap,
+         const std::string& url,
+         std::shared_ptr<PerIsolateOptions> per_isolate_opts);
   ~Worker();
 
   // Run the worker. This is only called from the worker thread.