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
window_->CloseNow();
}
void NativeWindowViews::Focus(bool focus) {
  
  if (!IsVisible())
    return;
  if (focus) {
#if defined(OS_WIN)
    window_->Activate();
#elif defined(USE_X11)
    
    ::Window window = GetAcceleratedWidget();
    XDisplay* xdisplay = gfx::GetXDisplay();
    SendClientEvent(xdisplay, window, "_NET_ACTIVE_WINDOW");
    XMapRaised(xdisplay, window);
#endif
  } else {
    window_->Deactivate();
  }
}
bool NativeWindowViews::IsFocused() {
  return window_->IsActive();
}
void NativeWindowViews::Show() {