* [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.13
* **Operating System:** Windows 10

### Expected Behavior

When calling `browserWindow.setAlwaysOnTop(true)`, I expect the `always-on-top-changed` event to be called with the boolean `isAlwaysOnTop` parameter set to `true`, and vice versa.

### Actual Behavior

I experience the opposite of above: When calling `browserWindow.setAlwaysOnTop(true)`, my `always-on-top-changed` handler is called with `false`, and vice versa.

### To Reproduce

I don't have any JS code to share and I'm not a JS dev (I use F# and compile to JS with Fable). I think the issue should be easy to reproduce though.
shell/browser/native_window_views.cc
#elif defined(USE_X11)
  std::string name = Browser::Get()->GetName();
  
  params.wm_role_name = "browser-window";
  
  params.wm_class_name = base::ToLowerASCII(name);
  params.wm_class_class = name;
#endif
  widget()->Init(params);
  bool fullscreen = false;
  options.Get(options::kFullscreen, &fullscreen);
  std::string window_type;
  options.Get(options::kType, &window_type);
#if defined(USE_X11)
  
  window_state_watcher_.reset(new WindowStateWatcher(this));
  
  bool use_dark_theme = false;
  if (options.Get(options::kDarkTheme, &use_dark_theme) && use_dark_theme) {
    XDisplay* xdisplay = gfx::GetXDisplay();
    XChangeProperty(xdisplay, GetAcceleratedWidget(),
                    XInternAtom(xdisplay, "_GTK_THEME_VARIANT", x11::False),
                    XInternAtom(xdisplay, "UTF8_STRING", x11::False), 8,
                    PropModeReplace,
                    reinterpret_cast<const unsigned char*>("dark"), 4);
  }
  
  
  std::vector<::Atom> state_atom_list;
  bool skip_taskbar = false;