Remove Futures class, move methods to Future.

tests/lib/async/future_test.dart

 // Copyright (c) 2012, 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.
 
 library future_test;
 
 import 'dart:async';
 import 'dart:isolate';
 
 testImmediate() {
@@ skipping 58 matching lines @@
   int after1;
   int after2;
 
   var futures = [];
   futures.add(future.then((int v) { before = v; }));
   completer.complete(3);
   futures.add(future.then((int v) { after1 = v; }));
   futures.add(future.then((int v) { after2 = v; }));
 
   var port = new ReceivePort();
-  new Future.wait(futures).then((_) {
+  Future.wait(futures).then((_) {
     Expect.equals(3, before);
     Expect.equals(3, after1);
     Expect.equals(3, after2);
     port.close();
   });
 }
 
 // Tests for [catchError]
 
 testException() {
@@ skipping 459 matching lines @@
   testFutureWhenErrorFutureValue();
   testFutureWhenValueFutureError();
   testFutureWhenErrorFutureError();
 
   testFutureThenThrowsAsync();
   testFutureCatchThrowsAsync();
   testFutureWhenThrowsAsync();
   testFutureCatchRethrowsAsync();
 }