### 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.3
* **Operating System:**
  * Windows 10 (1809)
* **Last Known Working Electron version:**:
  * 5.0.1

### Expected Behavior
Dragging your mouse to the bottom of the screen with a maximized frameless window and a hidden Windows taskbar should make the taskbar appear.

### Actual Behavior
The taskbar does not appear.

### To Reproduce

* Ensure you have Taskbar hiding enabled
![image](https://user-images.githubusercontent.com/144914/57793291-d12d9000-76f5-11e9-8c63-178e928a5358.png)

```sh
$ git clone https://github.com/adill/electron-quick-start -b no-taskbar-unhide
$ npm install
$ npm start || electron .
```

* Move your mouse to the bottom of the screen

### Screenshots

### Additional Information

atom/browser/native_window_views_win.cc
return "microphone-volume-up";
    case APPCOMMAND_HELP:
      return "help";
    case APPCOMMAND_FIND:
      return "find";
    case APPCOMMAND_NEW:
      return "new";
    case APPCOMMAND_OPEN:
      return "open";
    case APPCOMMAND_CLOSE:
      return "close";
    case APPCOMMAND_SAVE:
      return "save";
    case APPCOMMAND_PRINT:
      return "print";
    case APPCOMMAND_UNDO:
      return "undo";
    case APPCOMMAND_REDO:
      return "redo";
    case APPCOMMAND_COPY:
      return "copy";
    case APPCOMMAND_CUT:
      return "cut";
    case APPCOMMAND_PASTE:
      return "paste";
    case APPCOMMAND_REPLY_TO_MAIL:
      return "reply-to-mail";
    case APPCOMMAND_FORWARD_MAIL:
      return "forward-mail";
    case APPCOMMAND_SEND_MAIL: