src: add unique_ptr equivalent of CreatePlatform

This makes this bit of the embedder situation a bit easier to use.

PR-URL: #30467
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Author: addaleax

src/api/environment.cc

@@ -490,13 +490,20 @@ MultiIsolatePlatform* GetMainThreadMultiIsolatePlatform() {
 MultiIsolatePlatform* CreatePlatform(
     int thread_pool_size,
     node::tracing::TracingController* tracing_controller) {
-  return new NodePlatform(thread_pool_size, tracing_controller);
+  return MultiIsolatePlatform::Create(thread_pool_size, tracing_controller)
+      .release();
 }
 
 void FreePlatform(MultiIsolatePlatform* platform) {
   delete platform;
 }
 
+std::unique_ptr<MultiIsolatePlatform> MultiIsolatePlatform::Create(
+    int thread_pool_size,
+    node::tracing::TracingController* tracing_controller) {
+  return std::make_unique<NodePlatform>(thread_pool_size, tracing_controller);
+}
+
 MaybeLocal<Object> GetPerContextExports(Local<Context> context) {
   Isolate* isolate = context->GetIsolate();
   EscapableHandleScope handle_scope(isolate);

src/node.h

@@ -316,6 +316,10 @@ class NODE_EXTERN MultiIsolatePlatform : public v8::Platform {
   virtual void AddIsolateFinishedCallback(v8::Isolate* isolate,
                                           void (*callback)(void*),
                                           void* data) = 0;
+
+  static std::unique_ptr<MultiIsolatePlatform> Create(
+      int thread_pool_size,
+      node::tracing::TracingController* tracing_controller = nullptr);
 };
 
 enum IsolateSettingsFlags {
@@ -467,6 +471,7 @@ NODE_EXTERN Environment* GetCurrentEnvironment(v8::Local<v8::Context> context);
 // it returns nullptr.
 NODE_EXTERN MultiIsolatePlatform* GetMainThreadMultiIsolatePlatform();
 
+// Legacy variants of MultiIsolatePlatform::Create().
 NODE_EXTERN MultiIsolatePlatform* CreatePlatform(
     int thread_pool_size,
     node::tracing::TracingController* tracing_controller);