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### 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
const std::string& level,
                                       int relativeLevel,
                                       std::string* error) {
  if (z_order != widget()->GetZOrderLevel())
    NativeWindow::NotifyWindowAlwaysOnTopChanged();
  widget()->SetZOrderLevel(z_order);
#if defined(OS_WIN)
  
  behind_task_bar_ = false;
  if (z_order != ui::ZOrderLevel::kNormal) {
    
    
    static const std::vector<std::string> levels = {
        "floating", "torn-off-menu", "modal-panel", "main-menu", "status"};
    behind_task_bar_ = base::Contains(levels, level);
  }
#endif
  MoveBehindTaskBarIfNeeded();
}
ui::ZOrderLevel NativeWindowViews::GetZOrderLevel() {
  return widget()->GetZOrderLevel();
}
void NativeWindowViews::Center() {