Move Iterable implementation to collection.

sdk/lib/_internal/compiler/implementation/types/types.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 types;
 
-import 'dart:collection' show Queue;
+import 'dart:collection' show Queue, IterableBase;
 
 import '../dart2jslib.dart' hide Selector;
 import '../js_backend/js_backend.dart' show JavaScriptBackend;
 import '../tree/tree.dart';
 import '../elements/elements.dart';
 import '../native_handler.dart' as native;
 import '../util/util.dart';
 import '../universe/universe.dart';
 import 'simple_types_inferrer.dart' show SimpleTypesInferrer;
 import '../dart_types.dart';
@@ skipping 86 matching lines @@
    */
   TypeMask getGuaranteedTypeOfSelector(Selector selector) {
     return measure(() {
       if (typesInferrer != null) {
         return typesInferrer.getTypeOfSelector(selector);
       }
       return null;
     });
   }
 }