title: Chrome Extension fetch function not sending cookies
body: <p>I have a chrome extension that does an ajax call using the <code>fetch</code> function to my server running laravel.</p>
  
  <p>manifest perfmissions</p>
  
  <pre><code>"permissions": [
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "activeTab",
    "tabs",
    "cookies",
    "&lt;all_urls&gt;"
  ],
  </code></pre>
  
  <p>fetch call</p>
  
  <pre><code>fetch(this.url, {
    credentials: 'include',
    method: 'post',
    headers: {
      "Content-type": "application/x-www-form-urlencoded"
    },
    body: encodeDataToURL(telemetry)
  })
  .then(function (data) {
    console.log('Request succeeded with JSON response', data);
  })
  .catch(function (error) {
    console.log('Request failed', error);
  });
  </code></pre>
  
  <p>Cookies</p>
  
  <p><code>siusession=eyJpdiI6InlRS2wyb1BCZnJSSGtUaXVRelV4M3c9PSIsInZhbHVlIjoiRThteUk4MmVxeXV6a1N5ZUxTaFpxcUtSazJQRE1ZUUNQUWlBREVTdHRQM2pjNEVJUVUxd3gwM1JZMDNjOXR2TyIsIm1hYyI6ImUwMGQyNmAAhwQ3YWQ4YzRhOWVhYTk2ZjI2NDgwNTljNDE2YWU5NTdlZWM1MThiZWJjYzI3NmZjZWRhOGRlMzIifQ%3D%3D; expires=Tue, 25-Sep-2018 04:28:56 GMT; Max-Age=28800; path=/; secure; httponly; samesite=lax</code></p>
  
  <p>I have a opened session on my browser to that domain, which makes me having cookies with the <code>Session ID</code> and <code>XSRF-TOKEN</code>.</p>
  
  <p>The problem is, it doesn't send the cookies with the call.
  And on firefox, the same exact code and manifest it does send the browser cookies with the call.</p>
  
  <p>What can be wrong? Does chrome require some sort of different permissions or another way to make the call including cookies?</p>