app-indexed-db无法验证会话错误

Question

我使用Polymer Element app-indexeddb-mirror进行简单测试，失败并出现错误＆＃34;无法验证会话＆＃34;。我已经在浏览器上强制清除缓存并且仍然存在相同的问题。任何帮助都会受到极大的折磨！谢谢！

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<app-indexeddb-mirror log id="idb" data="{{item}}" worker-url="{{workerUrl}}" key="sale" persisted-data="{{persistedItem}}" online="[[online]]">
    </app-indexeddb-mirror>

    <template is="dom-repeat" items="{{persistedItem}}" as="item">
      <div>[[item.name]]</div>
    </template>
  </template>

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Uncaught TypeError: Cannot read property 'validateSession' of undefined
    at HTMLElement.<anonymous> (app-indexeddb-mirror.html:249)
    at HTMLElement._enqueueTransaction (app-storage-behavior.html:332)
    at HTMLElement.__updatePersistedData (app-indexeddb-mirror.html:248)
    at HTMLElement._complexObserverEffect (polymer.html:1672)
    at HTMLElement._effectEffects (polymer.html:1507)
    at HTMLElement._propertySetter (polymer.html:1491)
    at HTMLElement.__setProperty (polymer.html:1500)
    at HTMLElement._applyConfig (polymer.html:2111)
    at HTMLElement._afterClientsReady (polymer.html:2105)
    at HTMLElement._ready (polymer-mini.html:70)

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