title: uncaught security exception for the webkitNotifications.createNotification used in chrome extensions
body: <p>I was trying out to display a simple desktop notification thru chrome extensions. But I keep this error message:</p>
  
  <pre><code>Uncaught SecurityError: An attempt was made to break through the security policy of the user agent.
  </code></pre>
  
  <p>This is my manifest file:</p>
  
  <pre><code>{
    "name": "My extension",
    "version": "1.0",
    "manifest_version": 2,
    "content_scripts": [
      {
        "matches": ["myurl/*"],
         "js": ["contentScript.js"]
      }
    ],
    "permissions": [
      "notifications"
    ],
  
    "web_accessible_resources": [
      "chrome-logo.png"
    ]
  }
  </code></pre>
  
  <p>the content script is :</p>
  
  <pre><code> var notification = webkitNotifications.createNotification(
    'chrome-logo.png',  // icon url - can be relative
    'Hello!',  // notification title
    'Lorem ipsum...'  // notification body text
  );
  notification.show();
  </code></pre>
  
  <p>I added this line in the manifest.json file, but that didn't help either:</p>
  
  <pre><code>"content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self' ",
  </code></pre>
  
  <p>what is the work around for this error message?</p>