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
XEvent event = {};
  event.xclient.type = ClientMessage;
  event.xclient.send_event = True;
  event.xclient.message_type = XInternAtom(display, msg, False);
  event.xclient.window = window;
  event.xclient.format = 32;
  XSendEvent(display, DefaultRootWindow(display), False,
             SubstructureRedirectMask | SubstructureNotifyMask, &event);
  XFlush(display);
  return True;
}
#endif
class NativeWindowClientView : public views::ClientView {
 public:
  NativeWindowClientView(views::Widget* widget,
                         NativeWindowViews* contents_view)
      : views::ClientView(widget, contents_view) {
  }
  virtual ~NativeWindowClientView() {}
  bool CanClose() override {
    static_cast<NativeWindowViews*>(contents_view())->RequestToClosePage();
    return false;
  }
 private:
  DISALLOW_COPY_AND_ASSIGN(NativeWindowClientView);
};
}  
NativeWindowViews::NativeWindowViews(