Roll to pickup pool changes

packages/matcher/lib/src/map_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.
 
 import 'interfaces.dart';
 import 'util.dart';
 
 /// Returns a matcher which matches maps containing the given [value].
 Matcher containsValue(value) => new _ContainsValue(value);
 
 class _ContainsValue extends Matcher {
   final _value;
 
   const _ContainsValue(this._value);
 
   bool matches(item, Map matchState) => item.containsValue(_value);
   Description describe(Description description) =>
       description.add('contains value ').addDescriptionOf(_value);
 }
 
 /// Returns a matcher which matches maps containing the key-value pair
 /// with [key] => [value].
 Matcher containsPair(key, value) =>
     new _ContainsMapping(key, wrapMatcher(value));
 
 class _ContainsMapping extends Matcher {
   final _key;
   final Matcher _valueMatcher;
 
-  const _ContainsMapping(this._key, Matcher this._valueMatcher);
+  const _ContainsMapping(this._key, this._valueMatcher);
 
   bool matches(item, Map matchState) =>
       item.containsKey(_key) && _valueMatcher.matches(item[_key], matchState);
 
   Description describe(Description description) {
     return description
         .add('contains pair ')
         .addDescriptionOf(_key)
         .add(' => ')
         .addDescriptionOf(_valueMatcher);
   }
 
   Description describeMismatch(
       item, Description mismatchDescription, Map matchState, bool verbose) {
     if (!item.containsKey(_key)) {
       return mismatchDescription
           .add(" doesn't contain key ")
           .addDescriptionOf(_key);
     } else {
       mismatchDescription
           .add(' contains key ')
           .addDescriptionOf(_key)
           .add(' but with value ');
       _valueMatcher.describeMismatch(
           item[_key], mismatchDescription, matchState, verbose);
       return mismatchDescription;
     }
   }
 }