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/api/atom_api_window.cc
window_->SetRepresentedFilename(filename);
}
std::string Window::GetRepresentedFilename() {
  return window_->GetRepresentedFilename();
}
void Window::SetDocumentEdited(bool edited) {
  window_->SetDocumentEdited(edited);
}
bool Window::IsDocumentEdited() {
  return window_->IsDocumentEdited();
}
void Window::SetIgnoreMouseEvents(bool ignore) {
  return window_->SetIgnoreMouseEvents(ignore);
}
void Window::SetContentProtection(bool enable) {
  return window_->SetContentProtection(enable);
}
void Window::SetFocusable(bool focusable) {
  return window_->SetFocusable(focusable);
}
void Window::SetProgressBar(double progress) {
  window_->SetProgressBar(progress);
}
void Window::SetOverlayIcon(const gfx::Image& overlay,
                            const std::string& description) {
  window_->SetOverlayIcon(overlay, description);
}
bool Window::SetThumbarButtons(mate::Arguments* args) {