bool is_mobile_optimized = IsMobileOptimizedFrame(frame.metadata);
  input_router_->NotifySiteIsMobileOptimized(is_mobile_optimized);
  if (touch_emulator_)
    touch_emulator_->SetDoubleTapSupportForPageEnabled(!is_mobile_optimized);

I think it might be possible to execute this code on Chrome OS if we use devtools device emulation. We need to figure out an alternative way to propagate this information.