text: // Copyright 2016 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.
  
  var saw_requests = [];
  
  self.addEventListener('fetch', event => {
    saw_requests.push(event.request.url);
  });
  
  self.addEventListener('message', event => {
    event.source.postMessage(saw_requests);
  });
  