Allow Object when doing lookups.

samples/swarm/swarm_ui_lib/observable/observable.dart

 // Copyright (c) 2011, 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 observable;
 
 import 'dart:collection';
 
 part 'ChangeEvent.dart';
 part 'EventBatch.dart';
@@ skipping 195 matching lines @@
     recordListRemove(length, result);
     return result;
   }
 
   T removeAt(int index) {
     T result = _internal.removeAt(index);
     recordListRemove(index, result);
     return result;
   }
 
-  int indexOf(T element, [int start = 0]) {
+  int indexOf(Object element, [int start = 0]) {
     return _internal.indexOf(element, start);
   }
 
-  int lastIndexOf(T element, [int start = null]) {
+  int lastIndexOf(Object element, [int start = null]) {
     if (start == null) start = length - 1;
     return _internal.lastIndexOf(element, start);
   }
 
   bool removeFirstElement(T element) {
     // the removeAt above will record the event.
     return (removeAt(indexOf(element, 0)) != null);
   }
 
   int removeAllElements(T element) {
@@ skipping 44 matching lines @@
   }
 
   List sublist(int start, [int end]) {
     throw new UnimplementedError();
   }
 
   Iterable getRange(int start, int end) {
     throw new UnimplementedError();
   }
 
-  bool contains(T element) {
+  bool contains(Object element) {
     throw new UnimplementedError();
   }
 
   T reduce(T combine(T previousValue, T element)) {
     throw new UnimplementedError();
   }
 
   dynamic fold(var initialValue,
                dynamic combine(var previousValue, T element)) {
     throw new UnimplementedError();
   }
 
   // Iterable<T>:
   Iterator<T> get iterator => _internal.iterator;
 
   // Collection<T>:
   Iterable<T> where(bool f(T element)) => _internal.where(f);
   Iterable map(f(T element)) => _internal.map(f);
   Iterable expand(Iterable f(T element)) => _internal.expand(f);
   List<T> skip(int count) => _internal.skip(count);
   List<T> take(int count) => _internal.take(count);
   bool every(bool f(T element)) => _internal.every(f);
   bool any(bool f(T element)) => _internal.any(f);
   void forEach(void f(T element)) { _internal.forEach(f); }
   String join([String separator = ""]) => _internal.join(separator);
-  T firstWhere(bool test(T value), {T orElse()}) {
+  dynamic firstWhere(bool test(T value), {Object orElse()}) {
     return _internal.firstWhere(test, orElse: orElse);
   }
-  T lastWhere(bool test(T value), {T orElse()}) {
+  dynamic lastWhere(bool test(T value), {Object orElse()}) {
     return _internal.lastWhere(test, orElse: orElse);
   }
   T singleWhere(bool test(T value)) {
     return _internal.singleWhere(test);
   }
   T elementAt(int index) {
     return _internal.elementAt(index);
   }
   Map<int, T> asMap() {
     return _internal.asMap();
@@ skipping 21 matching lines @@
     // Only fire on an actual change.
     if (!identical(newValue, _value)) {
       final oldValue = _value;
       _value = newValue;
       recordPropertyUpdate("value", newValue, oldValue);
     }
   }
 
   T _value;
 }