We can get the content size and the window size, but not the chrome position.

At the moment we do this:

```
leftBorderWidth = (windowWidth - contentWidth) / 2;
titlebarHeight = windowHeight - (contentHeight + leftBorderWidth);
```

which makes some assumptions so therefore feels a bit wrong.

it would be nice if alongside getContentSize (https://github.com/electron/electron/blob/master/docs/api/browser-window.md#wingetcontentsize) there was a getContentOffset.

I've been looking at the C++ - https://github.com/electron/electron/blob/e05804848f98959d63337aacd9047cd579c5b23f/chromium_src/extensions/browser/app_window/size_constraints.cc and I don't see an easy way to get this information - do you have any ideas or pointers if you accept this as a feature request?

atom/browser/api/atom_api_window.cc
#if defined(OS_WIN)
  std::vector<TaskbarHost::ThumbarButton> buttons;
  if (!args->GetNext(&buttons)) {
    args->ThrowError();
    return false;
  }
  auto window = static_cast<NativeWindowViews*>(window_.get());
  return window->taskbar_host().SetThumbarButtons(
      window->GetAcceleratedWidget(), buttons);
#else
  return false;
#endif
}
void Window::SetMenu(v8::Isolate* isolate, v8::Local<v8::Value> value) {
  mate::Handle<Menu> menu;
  if (value->IsObject() &&
      mate::V8ToString(value->ToObject()->GetConstructorName()) == "Menu" &&
      mate::ConvertFromV8(isolate, value, &menu)) {
    menu_.Reset(isolate, menu.ToV8());
    window_->SetMenu(menu->model());
  } else if (value->IsNull()) {
    menu_.Reset();
    window_->SetMenu(nullptr);
  } else {
    isolate->ThrowException(v8::Exception::TypeError(
        mate::StringToV8(isolate, "Invalid Menu")));
  }
}
void Window::SetAutoHideMenuBar(bool auto_hide) {