Support a @Timeout annotation.

test/runner/browser/runner_test.dart

 // Copyright (c) 2015, 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.
 
 @TestOn("vm")
 
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:test/src/util/io.dart';
@@ skipping 240 matching lines @@
     print("Hello,");
     return new Future(() => print("world!"));
   });
 }
 """);
 
     var result = _runUnittest(["-p", "chrome", "test.dart"]);
     expect(result.stdout, contains("Hello,\nworld!\n"));
     expect(result.exitCode, equals(0));
   });
+
+  test("respects top-level @Timeout declarations", () {
+    new File(p.join(_sandbox, "test.dart")).writeAsStringSync('''
+@Timeout(const Duration(seconds: 0))
+
+import 'dart:async';
+
+import 'package:test/test.dart';
+
+void main() {
+  test("timeout", () {});
+}
+''');
+
+    var result = _runUnittest(["-p", "chrome", "test.dart"]);
+    expect(result.stdout, contains("Test timed out after 0 seconds."));
+    expect(result.stdout, contains("-1: Some tests failed."));
+  });
 }
 
 ProcessResult _runUnittest(List<String> args) =>
     runUnittest(args, workingDirectory: _sandbox);