During upgrade to the Chromium 61 we have switched from GTK2 to GTK3
and now we have a few warnings about stuff being deprecated in GTK3.
Check any Linux build to get a list of them.

/cc @zcbenz 
atom/browser/ui/views/menu_bar.cc
for (int i = 0; i < child_count(); ++i)
    static_cast<SubmenuButton*>(child_at(i))->SetAcceleratorVisibility(visible);
}
int MenuBar::GetAcceleratorIndex(base::char16 key) {
  for (int i = 0; i < child_count(); ++i) {
    SubmenuButton* button = static_cast<SubmenuButton*>(child_at(i));
    if (button->accelerator() == key)
      return i;
  }
  return -1;
}
void MenuBar::ActivateAccelerator(base::char16 key) {