Fix indexeddb_4_test.

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 22 matching lines @@
         } catch (IDBDatabaseException e) { }
         db.createObjectStore(STORE_NAME);
         writeItems(0);
       })
     );
     request.on.error.add(fail('setVersion error'));
   }
 
   writeItems(int index) {
     if (index < 100) {
-      var transaction = db.transaction([STORE_NAME], IDBTransaction.READ_WRITE);
+      var transaction = db.transaction([STORE_NAME], 'readwrite');
       var request = transaction.objectStore(STORE_NAME)
           .put('Item $index', index);
       request.on.success.add(expectAsync1((e) {
           writeItems(index + 1);
         }
       ));
       request.on.error.add(fail('put'));
     }
   }
 
   fail(message) => (e) {
     guardAsync(() {
       Expect.fail('IndexedDB failure: $message'); 
     });
   };
 
   readAllViaCursor() {
-    IDBTransaction txn = db.transaction(STORE_NAME, IDBTransaction.READ_ONLY);
+    IDBTransaction txn = db.transaction(STORE_NAME, 'readonly');
     IDBObjectStore objectStore = txn.objectStore(STORE_NAME);
     IDBRequest cursorRequest = objectStore.openCursor();
     int itemCount = 0;
     int sumKeys = 0;
     int lastKey = null;
     cursorRequest.on.success.add(expectAsync1((e) {
       var cursor = e.target.result;
       if (cursor != null) {
         lastKey = cursor.key;
         itemCount += 1;
@@ skipping 38 matching lines @@
 }
 
 main() {
   useHtmlConfiguration();
 
   var test_ = new Test();
   test('prepare', test_.start);
   test('readAll1', test_.readAllViaCursor);
   test('readAll2', test_.readAllReversedViaCursor);
 }