Electron Releases

Description of Change

Follow-up to #54286, which took the upstream gin versions of this. These gin_helper types are only ever constructed on the stack for one binding call or one conversion, so holding their pointers in raw_ptr<> cost a BackupRefPtr acquire/release each time with nothing to protect. They are now STACK_ALLOCATED() with plain pointers:

• Invoker::args_ (our fork of the code https://crrev.com/c/8455902 changes), and DispatchToCallback takes the callback by const ref (https://crrev.com/c/8455325)
• ErrorThrower::isolate_ (per call, for every method taking a thrower)
• Handle<T>::object_ (per wrappable create/return)
• Promise::SettleScope::isolate_ (was already CPPGC_STACK_ALLOCATED())
• ObjectBuilder::isolate_ (per converted event payload)
• V8Serializer / V8Deserializer::isolate_ (per IPC message / MessagePort post)

Heap-held holders (PromiseBase, PersistentDictionary, CallbackHolderBase, KeyWeakMap) are unchanged.

Checklist

• PR description included

Release Notes

Notes: none