[indexeddb] Fix IndexedDBBrowserTest.ConnectionsClosedOnTabClose to retain the db.

content/test/data/indexeddb/version_change_blocked.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.
 
 function test()
 {
   if (document.location.hash === '#tab1') {
     prepareDatabase(function () { doSetVersion(2); });
   } else if (document.location.hash === '#tab2') {
     doSetVersion(3);
@@ skipping 31 matching lines @@
 {
   // Open the database and try a setVersion
   var openreq = window.indexedDB.open('version-change-blocked', version);
   openreq.onerror = unexpectedErrorCallback;
   var upgradeneededComplete = false;
   openreq.onblocked = function(e) {
     result('setVersion(' + version + ') blocked');
   };
   openreq.onupgradeneeded = function(e) {
     openreq.transaction.oncomplete = function(e2) {
+      db = openreq.result;
       result('setVersion(' + version + ') complete');
     };
   };
 }