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
return GetNativeWindow()->GetHost()->GetAcceleratedWidget();
}
#if defined(OS_WIN)
void NativeWindowViews::SetIcon(HICON window_icon, HICON app_icon) {
  
  window_icon_ = base::win::ScopedHICON(CopyIcon(window_icon));
  app_icon_ = base::win::ScopedHICON(CopyIcon(app_icon));
  HWND hwnd = GetAcceleratedWidget();
  SendMessage(hwnd, WM_SETICON, ICON_SMALL,
              reinterpret_cast<LPARAM>(window_icon_.get()));
  SendMessage(hwnd, WM_SETICON, ICON_BIG,
              reinterpret_cast<LPARAM>(app_icon_.get()));
}
#elif defined(USE_X11)
void NativeWindowViews::SetIcon(const gfx::ImageSkia& icon) {
  views::DesktopWindowTreeHostX11* tree_host =
      views::DesktopWindowTreeHostX11::GetHostForXID(GetAcceleratedWidget());
  static_cast<views::DesktopWindowTreeHost*>(tree_host)->SetWindowIcons(
      icon, icon);
}
#endif
void NativeWindowViews::SetEnabled(bool enable) {