Make Map.keys/values Iterables.

pkg/serialization/lib/src/serialization_rule.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.
 
 part of serialization;
 
 // TODO(alanknight): We should have an example and tests for subclassing
 // serialization rule rather than using the hard-coded ClosureToMap rule. And
 // possibly an abstract superclass that's designed to be subclassed that way.
 /**
@@ skipping 498 matching lines @@
   _LazyMap(this._raw, this._reader);
 
   Map _raw;
   Reader _reader;
 
   // This is the only operation that really matters.
   operator [](x) => _reader.inflateReference(_raw[x]);
 
   int get length => _raw.length;
   bool get isEmpty => _raw.isEmpty;
-  List get keys => _raw.keys;
+  Iterable get keys => _raw.keys;
   bool containsKey(x) => _raw.containsKey(x);
 
   // These operations will work, but may be expensive, and are probably
   // best avoided.
   get _inflated => keysAndValues(_raw).map(_reader.inflateReference);
   bool containsValue(x) => _inflated.containsValue(x);
-  List get values => _inflated.values;
+  Iterable get values => _inflated.values;
   void forEach(f) => _inflated.forEach(f);
 
   // These operations are all invalid
   _throw() => throw new UnsupportedError("Not modifiable");
   operator []=(x, y) => _throw();
   putIfAbsent(x, y) => _throw();
   remove(x) => _throw();
   clear() => _throw();
 }