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 (!ContainsKey(messages_callback_map_, message))
    return;
  messages_callback_map_.erase(message);
}
bool Window::IsWindowMessageHooked(UINT message) {
  return ContainsKey(messages_callback_map_, message);
}
void Window::UnhookAllWindowMessages() {
  messages_callback_map_.clear();
}
bool Window::SetThumbnailClip(const gfx::Rect& region) {
  auto window = static_cast<NativeWindowViews*>(window_.get());
  return window->taskbar_host().SetThumbnailClip(
      window_->GetAcceleratedWidget(), region);
}
#endif
#if defined(TOOLKIT_VIEWS)
void Window::SetIcon(mate::Handle<NativeImage> icon) {
#if defined(OS_WIN)
  static_cast<NativeWindowViews*>(window_.get())->SetIcon(
      icon->GetHICON(GetSystemMetrics(SM_CXSMICON)),
      icon->GetHICON(GetSystemMetrics(SM_CXICON)));
#elif defined(USE_X11)
  static_cast<NativeWindowViews*>(window_.get())->SetIcon(
      icon->image().AsImageSkia());
#endif
}
#endif
void Window::SetAspectRatio(double aspect_ratio, mate::Arguments* args) {