title: Cool way to reset the browser action badge?
body: <p>I have an extension that implements a browser action.
  Of course, the browser action is allways visible, but it has a special significance in certain urls.  So, I use filtered events to listen to those urls and set the proper badge</p>
  
  <pre><code>chrome.webNavigation.onDOMContentLoaded.addListener(
      function(tab){
          chrome.browserAction.setBadgeText({
              text:'bdge',
              tabId: tab
          });
      },
      {'url':[{hostSuffix: 'somedomain.com', pathPrefix: 'somePath/'}]}
  );
  </code></pre>
  
  <p>Is there some "elegant" way to reset the badge when the user navigates out from that page, without listening every single tab navigation?
  Should I execute a content script to hang on some exiting event and send a message?</p>
  
  <p>Thank you very much,</p>