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
double sheet_offset_x_;
  double sheet_offset_y_;
  
  
  double aspect_ratio_;
  gfx::Size aspect_ratio_extraSize_;
  
  NativeWindow* parent_;
  
  bool is_modal_;
  
  brightray::InspectableWebContents* inspectable_web_contents_;
  
  base::ObserverList<NativeWindowObserver> observers_;
  base::WeakPtrFactory<NativeWindow> weak_factory_;
  DISALLOW_COPY_AND_ASSIGN(NativeWindow);
};
class NativeWindowRelay :
    public content::WebContentsUserData<NativeWindowRelay> {
 public:
  explicit NativeWindowRelay(base::WeakPtr<NativeWindow> window)
    : key(UserDataKey()), window(window) {}
  void* key;
  base::WeakPtr<NativeWindow> window;
 private:
  friend class content::WebContentsUserData<NativeWindow>;
};
}  
#endif