Import wpt@a7e9c2abcf65b78fcf1c246fec6681c74e1bc352

third_party/WebKit/LayoutTests/external/wpt/service-workers/service-worker/resources/request-end-to-end-worker.js

 var port = undefined;
+// Create a then-able object that is never resolved.
+function createPending() {
+  return { then: createPending };
+}
 
 onmessage = function(e) {
   var message = e.data;
   if (typeof message === 'object' && 'port' in message) {
     port = message.port;
+
+    port.postMessage('received port');
+    // The ServiceWorker which handles the "message" event must persist long
+    // enough to handle the subsequent "fetch" event. To promote test
+    // simplicity, the worker prevents its own termination indefinitely via a
+    // then-able that is never resolved.
+    e.waitUntil(createPending());
   }
 };
 
 onfetch = function(e) {
   var headers = {};
   var errorNameWhileAppendingHeader;
   for (var header of e.request.headers) {
     var key = header[0], value = header[1];
     headers[key] = value;
   }
   var errorNameWhileAddingHeader = '';
   try {
     e.request.headers.append('Test-Header', 'TestValue');
   } catch (e) {
     errorNameWhileAppendingHeader = e.name;
   }
   port.postMessage({
       url: e.request.url,
       mode: e.request.mode,
       method: e.request.method,
       referrer: e.request.referrer,
       headers: headers,
       headerSize: e.request.headers.size,
       errorNameWhileAppendingHeader: errorNameWhileAppendingHeader
     });
 };