Remove need to instantiate Platform and make methods static.

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.
  */
 #library('test_pub');
 
 #import('dart:io');
 
 #import('../../../lib/unittest/unittest.dart');
 #import('../../lib/file_system.dart');
 
 void testOutput(String description, List<String> pubArgs, String expected,
     [int exitCode = 0]) {
   asyncTest(description, 1, () {
     // Find a dart executable we can use to run pub. Uses the one that the
     // test infrastructure uses.
     final scriptDir = new File(new Options().script).directorySync().path;
-    final platform = new Platform().operatingSystem();
+    final platform = Platform.operatingSystem();
     final dartBin = joinPaths(scriptDir,
         '../../../tools/testing/bin/$platform/dart');
 
     // Find the main pub entrypoint.
     final pubPath = joinPaths(scriptDir, '../../pub/pub.dart');
 
     final args = [pubPath];
     args.addAll(pubArgs);
 
     final process = new Process.start(dartBin, args);
@@ skipping 62 matching lines @@
     final message = new StringBuffer();
     message.add('Unexpected output:\n');
     for (var i = expected.length; i < actual.length; i++) {
       message.add(actual[i]);
       message.add('\n');
     }
 
     Expect.fail(message.toString());
   }
 }