Remove Collection, Collections and clean up List/Set/Queue implementations of retain/remove.

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;
 
 /**
  * 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
@@ skipping 27 matching lines @@
   bool containsValue(V value) {
     var found = false;
     forEach((_,v) {
       if (v == value) {
         found = true;
       }
     });
     return found;
   }
 
-  Collection<K> get keys {
+  Iterable<K> get keys {
     var keys = <K>[];
     forEach((k,_) => keys.add(k));
     return keys;
   }
 
-  Collection<V> get values {
+  Iterable<V> get values {
     var values = <V>[];
     forEach((_,v) => values.add(v));
     return values;
   }
 
   bool get isEmpty => length == 0;
   V putIfAbsent(K key, V ifAbsent()) {
     if (!containsKey(key)) {
       V value = this[key];
       this[key] = ifAbsent();
@@ skipping 99 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);
       }
     });
   }
 }