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/native_window.h
void RenderViewCreated(content::RenderViewHost* render_view_host) override;
  void BeforeUnloadDialogCancelled() override;
  void DidFirstVisuallyNonEmptyPaint() override;
  bool OnMessageReceived(const IPC::Message& message) override;
 private:
  
  void ScheduleUnresponsiveEvent(int ms);
  
  void NotifyWindowUnresponsive();
  
  void NotifyReadyToShow();
  
  bool has_frame_;
  
  bool transparent_;
  
  
  std::unique_ptr<SkRegion> draggable_region_;  
  
  extensions::SizeConstraints size_constraints_;
  
  bool enable_larger_than_screen_;
  
  bool is_closed_;
  
  
  base::CancelableClosure window_unresposive_closure_;