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_->SetMinimumSize(gfx::Size(width, height));
}
std::vector<int> Window::GetMinimumSize() {
  std::vector<int> result(2);
  gfx::Size size = window_->GetMinimumSize();
  result[0] = size.width();
  result[1] = size.height();
  return result;
}
void Window::SetMaximumSize(int width, int height) {
  window_->SetMaximumSize(gfx::Size(width, height));
}
std::vector<int> Window::GetMaximumSize() {
  std::vector<int> result(2);
  gfx::Size size = window_->GetMaximumSize();
  result[0] = size.width();
  result[1] = size.height();
  return result;
}
void Window::SetSheetOffset(double offsetY, mate::Arguments* args) {
  double offsetX = 0.0;
  args->GetNext(&offsetX);
  window_->SetSheetOffset(offsetX, offsetY);
}
void Window::SetResizable(bool resizable) {
  window_->SetResizable(resizable);
}
bool Window::IsResizable() {