 <p>I see only two good choices: </p> <ol> <li>make that site a webproxy</li> <li>use <code>unlimitedStorage</code> permission and store the urls in WebSQL database (it's also the fastest). Despite the general concern that it may be deprecated in Chrome after W3C stopped developing the specification in favor of IndexedDB I don't think it'll happen any time soon because <em>all</em> the other available storage options are either [much] slower or less functional.</li> </ol>