### 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.cc
#include "shell/browser/api/event_emitter.h"
#include <utility>
#include "content/public/browser/render_frame_host.h"
#include "native_mate/arguments.h"
#include "native_mate/dictionary.h"
#include "native_mate/object_template_builder.h"
#include "shell/browser/api/event.h"
#include "shell/common/node_includes.h"
#include "ui/events/event_constants.h"
namespace mate {
namespace {
v8::Persistent<v8::ObjectTemplate> event_template;
void PreventDefault(mate::Arguments* args) {