### 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
const DWORD obj_id = static_cast<DWORD>(l_param);
      if (obj_id != static_cast<DWORD>(OBJID_CLIENT)) {
        return false;
      }
      if (!IsScreenReaderActive()) {
        return false;
      }
      checked_for_a11y_support_ = true;
      auto* const axState = content::BrowserAccessibilityState::GetInstance();
      if (axState && !axState->IsAccessibleBrowser()) {
        axState->OnScreenReaderDetected();
        Browser::Get()->OnAccessibilitySupportChanged();
      }
      return false;
    }
    case WM_GETMINMAXINFO: {
      WINDOWPLACEMENT wp;
      wp.length = sizeof(WINDOWPLACEMENT);
      
      
      
      
      
      if (!last_normal_placement_bounds_.IsEmpty() &&
          GetWindowPlacement(GetAcceleratedWidget(), &wp)) {
        last_normal_placement_bounds_.set_size(gfx::Size(0, 0));
        wp.rcNormalPosition = last_normal_placement_bounds_.ToRECT();
        SetWindowPlacement(GetAcceleratedWidget(), &wp);
        last_normal_placement_bounds_ = gfx::Rect();
      }