title: chrome.tabs.executeScript thows error "Unchecked runtime.lastError while running tabs.executeScript: Cannot access contents of url ..."
body: <p>So I am trying to execute a script from external source like www.script.google.com in background.js. 
  But I get this error -</p>
  
  <pre><code>Unchecked runtime.lastError while running tabs.executeScript: Cannot access contents of url "chrome-devtools://devtools/bundled/devtools.html?&amp;remoteBase=https://chrome…&amp;dockSide=undocked&amp;toolbarColor=rgba(223,223,223,1)&amp;textColor=rgba(0,0,0,1)". Extension manifest must request permission to access this host.
  </code></pre>
  
  <p>What i am doing is sending message from popup.js to background.js
  In popup.js - </p>
  
  <pre><code> chrome.runtime.sendMessage({type:"addtask"});
  </code></pre>
  
  <p>In background.js - </p>
  
  <pre><code>chrome.runtime.onMessage.addListener(function(request, sender, sendResponse){
      if(request.type == "addtask")
      {
          chrome.tabs.executeScript(null,
                         {file:"https://script.google.com/url of script....."});
      }
  });
  </code></pre>
  
  <p>My manifest.json-</p>
  
  <pre><code>{
      "name": "Extension",
      "version": "0.0.1",
      "manifest_version": 2,
      "browser_action": {
          "default_popup": "popup.html"
      },
       "background": {
          "scripts": ["background.js"],
          "persistent": false
      },
      "content_scripts": [{
          "js": ["jquery.min.js","contentscript.js"],
          "matches": ["http://*/*","https://*/*"],
          "css" : ["feedback.css"]
      }],
      "permissions": [
            "storage","tabs","https://script.google.com"
          ],
      "web_accessible_resources": ["feedback.js","html2canvas.js","event.js"],
      "content_security_policy": "script-src 'self' https://script.google.com/*; object-src 'self'"
  }
  </code></pre>