chrome.webRequest.onCompleted.addListener(
  function (details) {
    console.log(details);
    console.log(document);
    // return { responseHeaders: details.responseHeaders};
  },
  {
    urls: ["<all_urls>"],
    types: [
      "main_frame",
      "sub_frame",
      "stylesheet",
      "script",
      "image",
      "object",
      "xmlhttprequest",
      "other"
    ]
  },
  ["responseHeaders", "extraHeaders"]
);