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.cc
if (!inspectable_web_contents_)
    return;
  inspectable_web_contents_->GetView()->SetDelegate(nullptr);
  inspectable_web_contents_ = nullptr;
  Observe(nullptr);
  FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
                    WillDestoryNativeObject());
  
  
  
  
  
  CloseImmediately();
  
  window_unresposive_closure_.Cancel();
}
void NativeWindow::RendererUnresponsive(content::WebContents* source) {