old_contents: // Add a listener so background knows when a tab has changed.
  // You need 'tabs' persmission, that's why we added it to manifest file.
  chrome.tabs.onUpdated.addListener(showIntercomAction);
  
  
  function showIntercomAction(tabId, changeInfo, tab) {
    if (tab.url.indexOf('actitime.distech-controls') > -1) {
      // Show icon for page action in the current tab.
      chrome.pageAction.show(tabId);
    }
  };
  
  
  
new_contents: //Global
  
  chrome.tabs.onUpdated.addListener(showIntercomAction);
  
  
  function showIntercomAction(tabId, changeInfo, tab) {
    if (tab.url.indexOf('actitime.distech-controls') > -1) {
      // Show icon for page action in the current tab.
      chrome.pageAction.show(tabId);
    }
  };
  
  
  
subject: Update background.js