when setLoggedInUser is used, surpress events when the site's notion of a...

when setLoggedInUser is used, surpress events when the site's notion of a logged in user is the same as that of browserid

example/rp/index.html

@@ -143,9 +143,6 @@ $(document).ready(function() {
       requiredEmail: requiredEmail
     });
   });
-
-  // explicitly trigger events at document load
-  navigator.id.setLoggedInUser(null);
 });
 
 </script>

resources/static/communication_iframe/start.js

@@ -39,8 +39,17 @@
     setRemoteOrigin(trans.origin);
 
     user.getSilentAssertion(loggedInUser, function(email, assertion) {
-      if (email && assertion) chan.notify({ method: 'login', params: assertion });
-      else chan.notify({ method: 'logout' });
+      if (email) {
+        // only send login events when the assertion is defined - when
+        // the 'loggedInUser' is already logged in, it's false - that is
+        // when the site already has the user logged in and does not want
+        // the resources or cost required to generate an assertion
+        if (assertion) chan.notify({ method: 'login', params: assertion });
+      } else if (loggedInUser !== null) {
+        // only send logout events when loggedInUser is not null, which is an
+        // indicator that the site thinks the user is logged out
+        chan.notify({ method: 'logout' });
+      }
     }, function(err) {
       chan.notify({ method: 'logout' });
     });