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)
  DWORD affinity = enable ? WDA_MONITOR : WDA_NONE;
  ::SetWindowDisplayAffinity(GetAcceleratedWidget(), affinity);
#endif
}
void NativeWindowViews::SetFocusable(bool focusable) {
#if defined(OS_WIN)
  LONG ex_style = ::GetWindowLong(GetAcceleratedWidget(), GWL_EXSTYLE);
  if (focusable)
    ex_style &= ~WS_EX_NOACTIVATE;
  else
    ex_style |= WS_EX_NOACTIVATE;
  ::SetWindowLong(GetAcceleratedWidget(), GWL_EXSTYLE, ex_style);
  SetSkipTaskbar(!focusable);
  Focus(false);
#endif
}
void NativeWindowViews::SetMenu(AtomMenuModel* menu_model) {