### 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.15
* **Operating System:**
  * Windows 10 64bit
* **Last Known Working Electron version:**
  * 5.0.8

### Expected Behavior
The window restores its size to what it used to be

### Actual Behavior
The window is shown in the smallest size

### To Reproduce
1) Maximize Window
2) Minimize Window
3) Restore Window (click on the icon in the taskbar)
4) Unmaximize Window

### Screenshots
![grafik](https://user-images.githubusercontent.com/10595986/61781949-84f18100-ae05-11e9-8983-17edb536427f.png)


shell/browser/native_window_views_win.cc
WPARAM w_param,
                                                  LPARAM l_param) {
  if (n_code < 0) {
    return CallNextHookEx(NULL, n_code, w_param, l_param);
  }
  
  
  
  if (w_param == WM_MOUSEMOVE) {
    for (auto* window : forwarding_windows_) {
      
      
      
      
      RECT client_rect;
      GetClientRect(window->legacy_window_, &client_rect);
      POINT p = reinterpret_cast<MSLLHOOKSTRUCT*>(l_param)->pt;
      ScreenToClient(window->legacy_window_, &p);
      if (PtInRect(&client_rect, p)) {
        WPARAM w = 0;  
        LPARAM l = MAKELPARAM(p.x, p.y);
        PostMessage(window->legacy_window_, WM_MOUSEMOVE, w, l);
      }
    }
  }
  return CallNextHookEx(NULL, n_code, w_param, l_param);
}
}