Fix issue with permissions extension API event listeners.

chrome/test/data/extensions/api_test/permissions/optional/background.html

 <script>
 
 var assertEq = chrome.test.assertEq;
 var assertFalse = chrome.test.assertFalse;
 var assertTrue = chrome.test.assertTrue;
 var fail = chrome.test.callbackFail;
 var pass = chrome.test.callbackPass;
 var listenOnce = chrome.test.listenOnce;
 
 var NOT_OPTIONAL_ERROR =
@@ skipping 258 matching lines @@
           pass(function(removed) {
         assertTrue(removed);
         chrome.experimental.permissions.getAll(pass(function(permissions) {
           assertTrue(checkPermSetsEq(initialPermissions, permissions));
         }));
         chrome.experimental.permissions.contains(
             {origins:['http://*.c.com/*']},
             pass(function(result) { assertFalse(result); }));
         doReq('http://c.com', pass(function(result) { assertFalse(result); }));
       }));
+    },
+
+    // Tests that the changed permissions have taken effect from inside the
+    // onAdded and onRemoved event listeners.
+    function eventListenerPermissions() {
+      listenOnce(chrome.experimental.permissions.onAdded,
+                 function(permissions) {
+        chrome.windows.getAll({populate: true}, pass(function() {
+          assertTrue(true);
+        }));
+      });
+      listenOnce(chrome.experimental.permissions.onRemoved,
+                 function(permissions) {
+        try {
+          chrome.windows.getAll({populate: true}, function() {
+            chrome.test.fail("Should not have tabs API permission.");
+          });
+        } catch (e) {
+          assertTrue(e.message.indexOf(NO_TABS_PERMISSION) == 0);
+        }
+      });
+
+      chrome.experimental.permissions.request(
+          {permissions: ['tabs']}, pass(function(granted) {
+        assertTrue(granted);
+        chrome.experimental.permissions.remove(
+            {permissions: ['tabs']}, pass(function() {
+          assertTrue(true);
+        }));
+      }));
     }
 
   ]);
 });
 </script>