Add 'useCache' to the service worker registration options.

See w3c/ServiceWorker#893 (comment)

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=141919403

Author: yossik

externs/browser/w3c_serviceworker.js

@@ -219,7 +219,7 @@ ServiceWorkerContainer.prototype.oncontrollerchange;
 ServiceWorkerContainer.prototype.onerror;
 
 /**
- * @typedef {{scope: string}}
+ * @typedef {{scope: (string|undefined), useCache: (boolean|undefined)}}
  */
 var RegistrationOptions;