Fix indexeddb tests to implement proper setVersion semantics.

tests/html/indexeddb_3_test.dart

 #library('IndexedDB3Test');
 #import('../../lib/unittest/unittest.dart');
 #import('../../lib/unittest/html_config.dart');
 #import('dart:html');
 
 // Read with cursor.
 
 final String DB_NAME = 'Test';
 final String STORE_NAME = 'TEST';
 final String VERSION = '1';
@@ skipping 14 matching lines @@
     // open call and listening to onversionchange.  Can we feature-detect the
     // difference and make it work?
     var request = db.setVersion(VERSION);
     request.on.success.add(
       expectAsync1((e) {
         try {
           // Nuke object store if it already exists.
           db.deleteObjectStore(STORE_NAME);
         } catch (IDBDatabaseException e) { }
         db.createObjectStore(STORE_NAME);
-        writeItems(0);
+
+        var transaction = e.target.result;
+        transaction.on.complete.add(expectAsync1((e) => writeItems(0)));
+        transaction.on.error.add(fail);
       })
     );
     request.on.error.add(fail('setVersion error'));
   }
 
   writeItems(int index) {
     if (index < 100) {
       var transaction = db.transaction([STORE_NAME], 'readwrite');
       var request = transaction.objectStore(STORE_NAME)
           .put('Item $index', index);
@@ skipping 64 matching lines @@
 }
 
 main() {
   useHtmlConfiguration();
 
   var test_ = new Test();
   test('prepare', test_.start);
   test('readAll1', test_.readAllViaCursor);
   test('readAll2', test_.readAllReversedViaCursor);
 }