code: function updateTabAction(tabId) {
      chrome.storage.sync.get("options", function(data) {
        if (!data.options || !data.options.showTomster) { return; }
        chrome.pageAction.show(tabId);
        setActionTitle(tabId);
      });
    }
docs: Update the tab's pageAction: https://developer.chrome.com/extensions/pageAction
  If the user has choosen to display it, the icon is shown and the title
  is updated to display the ClientApp's information in the tooltip.
  @param {Number} tabId - the current tab