Import latest WritableStream tests from upstream

third_party/WebKit/LayoutTests/http/tests/streams/writable-streams/close.js

 'use strict';
 
 if (self.importScripts) {
   self.importScripts('/resources/testharness.js');
   self.importScripts('../resources/test-utils.js');
   self.importScripts('../resources/recording-streams.js');
 }
 
 promise_test(() => {
   const ws = new WritableStream({
@@ skipping 77 matching lines @@
 
     assert_equals(writer.desiredSize, 0, 'desiredSize should be 0');
 
     let calledClose = false;
     return Promise.all([
       writer.ready.then(v => {
         assert_equals(v, undefined, 'ready promise should be fulfilled with undefined');
         assert_true(calledClose, 'ready should not be fulfilled before writer.close() is called');
         assert_array_equals(ws.events, ['write', 'a'], 'sink abort() should not be called');
       }),
-      delay(100).then(() => {
+      flushAsyncEvents().then(() => {
         writer.close();
         calledClose = true;
       })
     ]);
   });
 }, 'when close is called on a WritableStream in waiting state, ready promise should be fulfilled');
 
 promise_test(() => {
   let asyncCloseFinished = false;
   const ws = recordingWritableStream({
     close() {
-      return delay(50).then(() => {
+      return flushAsyncEvents().then(() => {
         asyncCloseFinished = true;
       });
     }
   });
 
   const writer = ws.getWriter();
   return writer.ready.then(() => {
     writer.write('a');
 
     writer.close();
@@ skipping 13 matching lines @@
     close() {
       return {
         then(onFulfilled, onRejected) { onRejected(rejection); }
       };
     }
   });
   return promise_rejects(t, rejection, ws.getWriter().close(), 'close() should return a rejection');
 }, 'returning a thenable from close() should work');
 
 done();