Ask for notification permission during extension installation.

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

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var assertEq = chrome.test.assertEq;
 var assertFalse = chrome.test.assertFalse;
 var assertTrue = chrome.test.assertTrue;
 var assertThrows = chrome.test.assertThrows;
 var fail = chrome.test.callbackFail;
 var pass = chrome.test.callbackPass;
@@ skipping 188 matching lines @@
             assertThrows(
               chrome.bookmarks.getTree, [function(){}],
               "'bookmarks' requires a different Feature that is not present.");
           }
       ));
     },
 
     // The user shouldn't have to approve permissions that have no warnings.
     function noPromptForNoWarnings() {
       chrome.permissions.request(
-          {permissions: ['notifications']},
+          {permissions: ['cookies']},
           pass(function(granted) {
         assertTrue(granted);
 
-        // Remove the notifications permission to return to normal.
+        // Remove the cookies permission to return to normal.
         chrome.permissions.remove(
-            {permissions: ['notifications']},
+            {permissions: ['cookies']},
             pass(function(removed) { assertTrue(removed); }));
       }));
     },
 
     // Make sure you can only access the white listed permissions.
     function whitelist() {
       var error_msg = NOT_WHITE_LISTED_ERROR.replace('*', 'cloudPrintPrivate');
       chrome.permissions.request(
           {permissions: ['cloudPrintPrivate']}, fail(error_msg));
       chrome.permissions.remove(
@@ skipping 79 matching lines @@
         assertTrue(granted);
         chrome.permissions.remove(
             {permissions: ['bookmarks']}, pass(function() {
           assertTrue(true);
         }));
       }));
     }
 
   ]);
 });