Don't abuse LevelDBObserver interface to pass GetAll result.

content/test/data/dom_storage/sanity_check.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 startTestSoon() {
   window.setTimeout(test, 0);
 }
 
 function test() {
   try {
     debug('Checking window.localStorage');
     sanityCheck(window.localStorage);
     debug('Checking window.sessionStorage');
     sanityCheck(window.sessionStorage);
-    done();
+    window.setTimeout(done, 0);
   } catch(e) {
     fail(e);
   }
 }
 
 function sanityCheck(storage) {
   storage["preload"] = "done";
   checkEqual("done", storage["preload"],
              "storage['preload'] != 'done' after addition");
 
@@ skipping 53 matching lines @@
 }
 
 function checkEqual(lhs, rhs, errorMessage) {
   if (lhs !== rhs)
     throw errorMessage;
 }
 
 function makeLargeString(minimumSize) {
   return Array(minimumSize).join("X");
 }