### 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
#ifndef SHELL_BROWSER_API_EVENT_EMITTER_H_
#define SHELL_BROWSER_API_EVENT_EMITTER_H_
#include <utility>
#include <vector>
#include "base/optional.h"
#include "content/public/browser/browser_thread.h"
#include "electron/shell/common/api/api.mojom.h"
#include "native_mate/wrappable.h"
#include "shell/common/api/event_emitter_caller.h"
namespace content {
class RenderFrameHost;
}
namespace mate {
namespace internal {
v8::Local<v8::Object> CreateJSEvent(
    v8::Isolate* isolate,
    v8::Local<v8::Object> object,
    content::RenderFrameHost* sender,
    base::Optional<electron::mojom::ElectronBrowser::MessageSyncCallback>
        callback);
v8::Local<v8::Object> CreateCustomEvent(v8::Isolate* isolate,
                                        v8::Local<v8::Object> object,
                                        v8::Local<v8::Object> event);
v8::Local<v8::Object> CreateEventFromFlags(v8::Isolate* isolate, int flags);
}  
template <typename T>
class EventEmitter : public Wrappable<T> {