Refactor Future constructors.

tests/standalone/io/http_auth_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'dart:crypto';
 import 'dart:io';
 import 'dart:isolate';
 import 'dart:uri';
@@ skipping 202 matching lines @@
 }
 
 void testLocalServerBasic() {
   HttpClient client = new HttpClient();
 
   client.authenticate = (Uri url, String scheme, String realm) {
     client.addCredentials(
         Uri.parse("http://127.0.0.1/basic"),
         "test",
         new HttpClientBasicCredentials("test", "test"));
-    return new Future.immediate(true);
+    return new Future.value(true);
   };
 
   HttpClientConnection conn =
       client.getUrl(Uri.parse("http://127.0.0.1/basic/test"));
   conn.onResponse = (HttpClientResponse response) {
     Expect.equals(HttpStatus.OK, response.statusCode);
     response.inputStream.onData = () => response.inputStream.read();
     response.inputStream.onClosed = () {
       client.shutdown();
     };
   };
 }
 
 void testLocalServerDigest() {
   HttpClient client = new HttpClient();
 
   client.authenticate = (Uri url, String scheme, String realm) {
     print("url: $url, scheme: $scheme, realm: $realm");
     client.addCredentials(
         Uri.parse("http://127.0.0.1/digest"),
         "test",
         new HttpClientDigestCredentials("test", "test"));
-    return new Future.immediate(true);
+    return new Future.value(true);
   };
 
   HttpClientConnection conn =
       client.getUrl(Uri.parse("http://127.0.0.1/digest/test"));
   conn.onResponse = (HttpClientResponse response) {
     Expect.equals(HttpStatus.OK, response.statusCode);
     response.inputStream.onData = () => response.inputStream.read();
     response.inputStream.onClosed = () {
       client.shutdown();
     };
   };
 }
 
 main() {
   testUrlUserInfo();
   testBasicNoCredentials();
   testBasicCredentials();
   testBasicAuthenticateCallback();
   // These teste are not normally run. They can be used for locally
   // testing with another web server (e.g. Apache).
   //testLocalServerBasic();
   //testLocalServerDigest();
 }