Implement author-constructible ReadableStream using V8 extras

third_party/WebKit/LayoutTests/http/tests/streams/resources/test-utils.js

+'use strict';
+
+self.getterRejects = (t, obj, getterName, target) => {
+  const getter = Object.getOwnPropertyDescriptor(obj, getterName).get;
+
+  return promise_rejects(t, new TypeError(), getter.call(target));
+};
+
+self.methodRejects = (t, obj, methodName, target) => {
+  const method = obj[methodName];
+
+  return promise_rejects(t, new TypeError(), method.call(target));
+};
+
+self.getterThrows = (obj, getterName, target) => {
+  const getter = Object.getOwnPropertyDescriptor(obj, getterName).get;
+
+  assert_throws(new TypeError(), () => getter.call(target), getterName + ' should throw a TypeError');
+};
+
+self.methodThrows = (obj, methodName, target, args) => {
+  const method = obj[methodName];
+
+  assert_throws(new TypeError(), () => method.apply(target, args), methodName + ' should throw a TypeError');
+};
+
+self.garbageCollect = () => {
+  if (self.gc) {
+    // Use --expose_gc for V8 (and Node.js)
+    // Exposed in SpiderMonkey shell as well
+    self.gc();
+  } else if (self.GCController) {
+    // Present in some WebKit development environments
+    GCController.collect();
+  } else {
+    /* eslint-disable no-console */
+    console.warn('Tests are running without the ability to do manual garbage collection. They will still work, but ' +
+      'coverage will be suboptimal.');
+    /* eslint-enable no-console */
+  }
+};
+
+self.delay = ms => new Promise(resolve => setTimeout(resolve, ms));