### 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.cc
if (options.Get(options::kSkipTaskbar, &skip_taskbar) && skip_taskbar) {
    state_atom_list.push_back(GetAtom("_NET_WM_STATE_SKIP_TASKBAR"));
  }
  
  if (fullscreen) {
    state_atom_list.push_back(GetAtom("_NET_WM_STATE_FULLSCREEN"));
  }
  if (parent) {
    SetParentWindow(parent);
    
    window_type = "dialog";
    
    if (is_modal())
      state_atom_list.push_back(GetAtom("_NET_WM_STATE_MODAL"));
  }
  if (!state_atom_list.empty())
    ui::SetAtomArrayProperty(GetAcceleratedWidget(), "_NET_WM_STATE", "ATOM",
                             state_atom_list);
  
  if (!window_type.empty())
    SetWindowType(GetAcceleratedWidget(), window_type);
#endif
#if defined(OS_WIN)
  if (!has_frame()) {
    
    
    DWORD frame_style = WS_CAPTION | WS_OVERLAPPED;
    if (resizable_)
      frame_style |= WS_THICKFRAME;
    if (minimizable_)