### Preflight Checklist

* [x] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
* [x] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
* [x] I have searched the issue tracker for an issue that matches the one I want to file, without success.

### Issue Details

* **Electron Version:** 6.0.0-beta.13
* **Operating System:** Windows 12

### Expected Behavior

The documentation for the App events `browser-window-created` and `web-contents-created` state that the first parameter is an `Event`. I therefore expect the first parameter to be an `Event`.

### Actual Behavior

The first parameter for both of these events is `undefined`. (The second parameter is a `BrowserWindow` and `WebContents`, respectively, as documented.)
shell/browser/api/event_emitter.h
public:
  typedef std::vector<v8::Local<v8::Value>> ValueArray;
  
  
  v8::Isolate* isolate() const { return Wrappable<T>::isolate(); }
  v8::Local<v8::Object> GetWrapper() const {
    return Wrappable<T>::GetWrapper();
  }
  v8::MaybeLocal<v8::Object> GetWrapper(v8::Isolate* isolate) const {
    return Wrappable<T>::GetWrapper(isolate);
  }
  
  template <typename... Args>
  bool EmitCustomEvent(base::StringPiece name,
                       v8::Local<v8::Object> event,
                       Args&&... args) {
    return EmitWithEvent(
        name, internal::CreateCustomEvent(isolate(), GetWrapper(), event),
        std::forward<Args>(args)...);
  }
  
  template <typename... Args>
  bool EmitWithFlags(base::StringPiece name, int flags, Args&&... args) {