title: CORS Issue in Chrome Developer Extension
body: <p>I am a novice in Chrome Extension Development and I am developing a Chrome <strong>Developer</strong> Extension (appears as a part of Developer Tools).
  This requirement is to make External Service (some URL )call which may or may not be in the same Server (of origin). From the documentation I see the extensions are not restricted by the Same Origin Policy. <a href="https://developer.chrome.com/extensions/xhr" rel="nofollow noreferrer">https://developer.chrome.com/extensions/xhr</a></p>
  
  <p>However I am running into CORS issue while I try to call an external service. </p>
  
  <p>The Manifest.json looks like the below one, where I have permission to all websites. </p>
  
  <pre><code>"permissions": [
          "tabs",
          "clipboardWrite",
          "http://*/*",
          "https://*/*"
      ],
  </code></pre>
  
  <p>In the code I am trying to call HTTP POST on some URL , the code looks like </p>
  
  <pre><code>gwUrl = 'http://services.odata.org/V2/(S(lts2i32bwwy01zoq4cxyscwt))/OData/OData.svc/Products';
  var xhr = new XMLHttpRequest();
  xhr.open("POST", gwUrl , true);
  xhr.setRequestHeader("Content-type", "application/json");
  xhr.onreadystatechange = function() {}
  xhr.send({ "ID":17, "Name": "Bread", "Description": "Whole grain bread"});      
  </code></pre>
  
  <p>I am getting the following Error.</p>
  
  <p><em>OPTIONS http//services.odata.org/V2/(S(lts2i32bwwy01zoq4cxyscwt))/OData/OData.svc/Products 501 (Not Implemented)</em></p>
  
  <p><em>XMLHttpRequest cannot load http//services.odata.org/V2/(S(lts2i32bwwy01zoq4cxyscwt))/OData/OData.svc/Products. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'chrome-extension://cdcbiglainpfeapfejdjdkldcehjakfi' is therefore not allowed access. The response had HTTP status code 501.</em></p>
  
  <p><a href="https://i.stack.imgur.com/U55gV.png" rel="nofollow noreferrer">Error Screenshot </a>
  Can anyone please guide me to fix the issue.</p>