Align source mirrors with runtime mirrors.

sdk/lib/_internal/compiler/implementation/mirrors/util.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 util;
+library dart2js.mirrors.util;
+
+import 'dart:collection' show Maps;
 
 /**
  * An abstract map implementation. This class can be used as a superclass for
  * implementing maps, requiring only the further implementation of the
  * [:operator []:], [:forEach:] and [:length:] methods to provide a fully
  * implemented immutable map.
  */
 abstract class AbstractMap<K, V> implements Map<K, V> {
   AbstractMap();
 
   AbstractMap.from(Map<K, V> other) {
     other.forEach((k,v) => this[k] = v);
   }
 
   void operator []=(K key, value) {
     throw new UnsupportedError('[]= is not supported');
   }
 
   void clear() {
     throw new UnsupportedError('clear() is not supported');
   }
-  
+
   void addAll(Map<K, V> other) {
     throw new UnsupportedError('addAll() is not supported');
   }
 
   bool containsKey(K key) {
     var found = false;
     forEach((k,_) {
       if (k == key) {
         found = true;
       }
@@ skipping 30 matching lines @@
       V value = this[key];
       this[key] = ifAbsent();
       return value;
     }
     return null;
   }
 
   V remove(K key) {
     throw new UnsupportedError('V remove(K key) is not supported');
   }
+
+  String toString() => Maps.mapToString(this);
 }
 
 /**
  * [ImmutableMapWrapper] wraps a (mutable) map as an immutable map where all
  * mutating operations throw [UnsupportedError] upon invocation.
  */
 class ImmutableMapWrapper<K, V> extends AbstractMap<K, V> {
   final Map<K, V> _map;
 
   ImmutableMapWrapper(this._map);
@@ skipping 81 matching lines @@
 
   void forEach(void f(K key, Vout value)) {
     _map.forEach((K k, Vin v) {
       var value = _filter(v);
       if (value != null) {
         f(k, value);
       }
     });
   }
 }