Cleanup MatchState in pub.

sdk/lib/_internal/pub/test/version_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 version_test;
 
 import 'package:unittest/unittest.dart';
 import 'test_pub.dart';
 import '../lib/src/utils.dart';
 import '../lib/src/version.dart';
@@ skipping 412 matching lines @@
     });
   });
 }
 
 class VersionConstraintMatcher implements Matcher {
   final List<Version> _expected;
   final bool _allow;
 
   VersionConstraintMatcher(this._expected, this._allow);
 
-  bool matches(item, MatchState matchState) => (item is VersionConstraint) &&
+  bool matches(item, Map matchState) => (item is VersionConstraint) &&
       _expected.every((version) => item.allows(version) == _allow);
 
   Description describe(Description description) =>
       description.add(' ${_allow ? "allows" : "does not allow"} versions');
 
   Description describeMismatch(item, Description mismatchDescription,
-      MatchState matchState, bool verbose) {
+      Map matchState, bool verbose) {
     if (item is! VersionConstraint) {
       mismatchDescription.add('was not a VersionConstraint');
       return mismatchDescription;
     }
 
     bool first = true;
     for (var version in _expected) {
       if (item.allows(version) != _allow) {
         if (first) {
           if (_allow) {
@@ skipping 16 matching lines @@
 
 Matcher allows(List<Version> versions) =>
     new VersionConstraintMatcher(versions, true);
 
 Matcher doesNotAllow(List<Version> versions) =>
     new VersionConstraintMatcher(versions, false);
 
 throwsIllegalArg(function) {
   expect(function, throwsA((e) => e is ArgumentError));
 }