  void WriteServiceWorkerFetchTestFiles() {
    WriteFile(FILE_PATH_LITERAL("sw.js"),
              "this.onactivate = function(event) {"
              "  event.waitUntil(self.clients.claim());"
              "};"
              "this.onfetch = function(event) {"
              "  event.respondWith("
              "      self.clients.matchAll().then(function(clients) {"
              "          clients.forEach(function(client) {"
              "              client.postMessage("
              "                'url:' + event.request.url + ', ' +"
              "                'mode:' + event.request.mode + ', ' +"
              "                'credentials:' + event.request.credentials"
              "              );"
              "            });"
              "          return fetch(event.request);"
              "        }));"
              "};");
    WriteFile(FILE_PATH_LITERAL("test.html"),
              "<script>"
              "navigator.serviceWorker.register('./sw.js', {scope: './'})"
              "  .then(function(reg) {"
              "      reg.addEventListener('updatefound', function() {"
              "          var worker = reg.installing;"
              "          worker.addEventListener('statechange', function() {"
              "              if (worker.state == 'activated')"
              "                document.title = 'READY';"
              "            });"
              "        });"
              "    });"
              "var reportOnFetch = true;"
              "var issuedRequests = [];"
              "function reportRequests() {"
              "  var str = '';"
              "  issuedRequests.forEach(function(data) {"
              "      str += data + '\\n';"
              "    });"
              "  window.domAutomationController.send(str);"
              "}"
              "navigator.serviceWorker.addEventListener("
              "    'message',"
              "    function(event) {"
              "      issuedRequests.push(event.data);"
              "      if (reportOnFetch) {"
              "        reportRequests();"
              "      }"
              "    }, false);"
              "</script>");
  }

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.