Implement author-constructible ReadableStream using V8 extras

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

+'use strict';
+
+self.getterRejects = function(test, obj, getterName, target, endTest) {
+    var getter = Object.getOwnPropertyDescriptor(obj, getterName).get;
+
+    getter.call(target).then(
+        test.step_func(function() { assert_unreached(getterName + ' should not fulfill'); }),
+        test.step_func(function(e) {
+            assert_throws(new TypeError(), function() { throw e; }, getterName + ' should reject with a TypeError');
+            if (endTest === true) {
+                test.done();
+            }
+        }));
+};
+
+self.methodRejects = function (test, obj, methodName, target, endTest) {
+    var method = obj[methodName];
+
+    method.call(target).then(
+        test.step_func(function() { assert_unreached(methodName + ' should not fulfill'); }),
+        test.step_func(function(e) {
+            assert_throws(new TypeError(), function() { throw e; }, methodName + ' should reject with a TypeError');
+            if (endTest === true) {
+                test.done();
+            }
+        }));
+};
+
+self.getterThrows = function (obj, getterName, target) {
+  var getter = Object.getOwnPropertyDescriptor(obj, getterName).get;
+
+    assert_throws(new TypeError(), function() { getter.call(target); }, getterName + ' should throw a TypeError');
+};
+
+self.methodThrows = function (obj, methodName, target) {
+    var method = obj[methodName];
+
+    assert_throws(new TypeError(), function() { method.call(target); }, 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 {
+        console.warn('Tests are running without the ability to do manual garbage collection. They will still work, but ' +
+          'coverage will be suboptimal.');
+    }
+};
+
+self.delay = ms => new Promise(resolve => setTimeout(resolve, ms));