* Electron Version 6.0.0-beta.12
* Operating System Windows 10 64 bit

Expected Behavior
webContents.print() should send print a job to the specified printer

Actual behavior
Nothing happens. Callback gets called much latter, for example on program exit.

To Reproduce
let print_options = { 
    silent: true,
    printBackground: true,
    deviceName: barcode_device_name 
}
print_window.webContents.print(print_options, (data) => {
    console.log(`print result: ${data}`)
})

Related to #17260
shell/browser/api/atom_api_web_contents.cc
return type_;
}
bool WebContents::Equal(const WebContents* web_contents) const {
  return ID() == web_contents->ID();
}
void WebContents::LoadURL(const GURL& url, const mate::Dictionary& options) {
  if (!url.is_valid() || url.spec().size() > url::kMaxURLChars) {
    Emit("did-fail-load", static_cast<int>(net::ERR_INVALID_URL),
         net::ErrorToShortString(net::ERR_INVALID_URL),
         url.possibly_invalid_spec(), true);
    return;
  }
  content::NavigationController::LoadURLParams params(url);
  if (!options.Get("httpReferrer", &params.referrer)) {
    GURL http_referrer;
    if (options.Get("httpReferrer", &http_referrer))
      params.referrer =
          content::Referrer(http_referrer.GetAsReferrer(),
                            network::mojom::ReferrerPolicy::kDefault);
  }
  std::string user_agent;
  if (options.Get("userAgent", &user_agent))
    web_contents()->SetUserAgentOverride(user_agent, false);
  std::string extra_headers;
  if (options.Get("extraHeaders", &extra_headers))
    params.extra_headers = extra_headers;
  scoped_refptr<network::ResourceRequestBody> body;
  if (options.Get("postData", &body)) {
    params.post_data = body;