docs: function getTabsWithURL(aUrl) {
    var tabs = [ ];
  
    var uri = utils.createURI(aUrl, null, null);
  
    var wm = Cc["@mozilla.org/appshell/window-mediator;1"].
             getService(Ci.nsIWindowMediator);
    var winEnum = wm.getEnumerator("navigator:browser");
  
    // Iterate through all windows
    while (winEnum.hasMoreElements()) {
      var window = winEnum.getNext();
   
      // Don't check windows which are about to close or don't have gBrowser set
      if (window.closed || !("gBrowser" in window))
        continue;
  
      // Iterate through all tabs in the current window
      var browsers = window.gBrowser.browsers;
      for (var i = 0; i < browsers.length; i++) {
        var browser = browsers[i];
        if (browser.currentURI.equals(uri)) {
          tabs.push({
            controller : new mozmill.controller.MozMillController(window),
            index : i
          });
        }
      }
    }
  
    return tabs;
  }