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_views.cc
#if defined(OS_WIN)
  if (thick_frame_)
    FlipWindowStyle(GetAcceleratedWidget(), resizable, WS_THICKFRAME);
#elif defined(USE_X11)
  if (resizable != resizable_) {
    
    
    if (resizable) {
      SetContentSizeConstraints(old_size_constraints_);
    } else {
      old_size_constraints_ = GetContentSizeConstraints();
      resizable_ = false;
      gfx::Size content_size = GetContentSize();
      SetContentSizeConstraints(
          extensions::SizeConstraints(content_size, content_size));
    }
  }
#endif
  resizable_ = resizable;
}
bool NativeWindowViews::IsResizable() {