

### Issue Details

* **Electron Version:**
  * 7.1.1
* **Operating System:**
  *  Windows 10 (1803) 
* **Last Known Working Electron version:**
  * 6.1.3

### Expected Behavior
dialog.showMessageBox
https://electronjs.org/docs/api/dialog#dialogshowmessageboxbrowserwindow-options
Returns Promise<Object> - resolves with a promise containing the following properties:
- response Number - The index of the clicked button.
- **checkboxChecked** Boolean - The checked state of the checkbox if checkboxLabel was set. Otherwise false.

### Actual Behavior
checkboxChecked do not change



shell/browser/ui/message_box.h
MESSAGE_BOX_NONE = 0,
  MESSAGE_BOX_NO_LINK = 1 << 0,
};
struct MessageBoxSettings {
  electron::NativeWindow* parent_window = nullptr;
  MessageBoxType type = electron::MessageBoxType::kNone;
  std::vector<std::string> buttons;
  int default_id;
  int cancel_id;
  int options = electron::MessageBoxOptions::MESSAGE_BOX_NONE;
  std::string title;
  std::string message;
  std::string detail;
  std::string checkbox_label;
  bool checkbox_checked = false;
  gfx::ImageSkia icon;
  MessageBoxSettings();
  MessageBoxSettings(const MessageBoxSettings&);
  ~MessageBoxSettings();
};
int ShowMessageBoxSync(const MessageBoxSettings& settings);
typedef base::OnceCallback<void(int code, bool checkbox_checked)>
    MessageBoxCallback;
void ShowMessageBox(const MessageBoxSettings& settings,
                    MessageBoxCallback callback);
void ShowErrorBox(const base::string16& title, const base::string16& content);
}  
#endif