pkg/matcher: Reverting 36881,36896 while investigating dart2js checked crash

pkg/matcher/lib/src/future_matchers.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 matcher.future_matchers;
+part of matcher;
 
-import 'dart:async';
-
-import 'core_matchers.dart';
-import 'expect.dart';
-import 'interfaces.dart';
-
-/// Matches a [Future] that completes successfully with a value. Note that this
-/// creates an asynchronous expectation. The call to `expect()` that includes
-/// this will return immediately and execution will continue. Later, when the
-/// future completes, the actual expectation will run.
-///
-/// To test that a Future completes with an exception, you can use [throws] and
-/// [throwsA].
+/**
+ * Matches a [Future] that completes successfully with a value. Note that this
+ * creates an asynchronous expectation. The call to `expect()` that includes
+ * this will return immediately and execution will continue. Later, when the
+ * future completes, the actual expectation will run.
+ *
+ * To test that a Future completes with an exception, you can use [throws] and
+ * [throwsA].
+ */
 final Matcher completes = const _Completes(null, '');
 
-/// Matches a [Future] that completes succesfully with a value that matches
-/// [matcher]. Note that this creates an asynchronous expectation. The call to
-/// `expect()` that includes this will return immediately and execution will
-/// continue. Later, when the future completes, the actual expectation will run.
-///
-/// To test that a Future completes with an exception, you can use [throws] and
-/// [throwsA].
-///
-/// [id] is an optional tag that can be used to identify the completion matcher
-/// in error messages.
+/**
+ * Matches a [Future] that completes succesfully with a value that matches
+ * [matcher]. Note that this creates an asynchronous expectation. The call to
+ * `expect()` that includes this will return immediately and execution will
+ * continue. Later, when the future completes, the actual expectation will run.
+ *
+ * To test that a Future completes with an exception, you can use [throws] and
+ * [throwsA].
+ *
+ * [id] is an optional tag that can be used to identify the completion matcher
+ * in error messages.
+ */
 Matcher completion(matcher, [String id = '']) =>
     new _Completes(wrapMatcher(matcher), id);
 
 class _Completes extends Matcher {
   final Matcher _matcher;
   final String _id;
 
   const _Completes(this._matcher, this._id);
 
   bool matches(item, Map matchState) {
@@ skipping 19 matching lines @@
 
   Description describe(Description description) {
     if (_matcher == null) {
       description.add('completes successfully');
     } else {
       description.add('completes to a value that ').addDescriptionOf(_matcher);
     }
     return description;
   }
 }