Fix type annotation and comment.

utils/tests/pub/test_pub.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.
 
 /**
  * Test infrastructure for testing pub. Unlike typical unit tests, most pub
  * tests are integration tests that stage some stuff on the file system, run
  * pub, and then validate the results. This library provides an API to build
  * tests like that.
  */
@@ skipping 1450 matching lines @@
           "waiting for process $name to exit").transform((exitCode) {
         if (expectedExitCode != null) {
           expect(exitCode, equals(expectedExitCode));
         }
       });
     });
   }
 
   /// Wraps [source] and ensures it gets eagerly drained. We do this to make
   /// sure a process will exit even if we don't care about its output.
-  static Future<StringInputStream> _wrapStream(InputStream source) {
+  static StringInputStream _wrapStream(InputStream source) {
     return new StringInputStream(wrapInputStream(source));
   }
 
   /// Prints the remaining data in the process's stdout and stderr streams.
   /// Prints nothing if the straems are empty.
   Future _printStreams() {
     Future printStream(String streamName, StringInputStream stream) {
       return consumeStringInputStream(stream).transform((output) {
         if (output.isEmpty) return;
 
@@ skipping 155 matching lines @@
 /// calling [completion] is unnecessary.
 void expectLater(Future actual, matcher, {String reason,
     FailureHandler failureHandler, bool verbose: false}) {
   _schedule((_) {
     return actual.transform((value) {
       expect(value, matcher, reason: reason, failureHandler: failureHandler,
           verbose: false);
     });
   });
 }