Update charted to 0.4.8 and roll

packages/observe/lib/src/to_observable.dart

-// Copyright (c) 2013, 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 observe.src.to_observable;
-
-import 'package:observe/observe.dart';
-
-/// Converts the [Iterable] or [Map] to an [ObservableList] or [ObservableMap],
-/// respectively. This is a convenience function to make it easier to convert
-/// literals into the corresponding observable collection type.
-///
-/// If [value] is not one of those collection types, or is already [Observable],
-/// it will be returned unmodified.
-///
-/// If [value] is a [Map], the resulting value will use the appropriate kind of
-/// backing map: either [HashMap], [LinkedHashMap], or [SplayTreeMap].
-///
-/// By default this performs a deep conversion, but you can set [deep] to false
-/// for a shallow conversion. This does not handle circular data structures.
-/// If a conversion is peformed, mutations are only observed to the result of
-/// this function. Changing the original collection will not affect it.
-// TODO(jmesserly): ObservableSet?
-toObservable(value, {bool deep: true}) =>
-    deep ? _toObservableDeep(value) : _toObservableShallow(value);
-
-_toObservableShallow(value) {
-  if (value is Observable) return value;
-  if (value is Map) return new ObservableMap.from(value);
-  if (value is Iterable) return new ObservableList.from(value);
-  return value;
-}
-
-_toObservableDeep(value) {
-  if (value is Observable) return value;
-  if (value is Map) {
-    var result = new ObservableMap.createFromType(value);
-    value.forEach((k, v) {
-      result[_toObservableDeep(k)] = _toObservableDeep(v);
-    });
-    return result;
-  }
-  if (value is Iterable) {
-    return new ObservableList.from(value.map(_toObservableDeep));
-  }
-  return value;
-}