package:observe fix various api issues

pkg/mdv/test/mdv_test_utils.dart

Index: pkg/mdv/test/mdv_test_utils.dart
diff --git a/pkg/mdv/test/mdv_test_utils.dart b/pkg/mdv/test/mdv_test_utils.dart
index 97893de19d2d38c4dd2dc9e4aea57f56656be185..7f7650694bb74bf260a5d6e2058110379e633662 100644
--- a/pkg/mdv/test/mdv_test_utils.dart
+++ b/pkg/mdv/test/mdv_test_utils.dart
@@ -17,15 +17,6 @@ final bool parserHasNativeTemplate = () {
       div.firstChild.firstChild.tagName == 'TEMPLATE';
 }();
 
-toSymbolMap(Map map) {
-  var result = new ObservableMap.linked();
-  map.forEach((key, value) {
-    if (value is Map) value = toSymbolMap(value);
-    result[new Symbol(key)] = value;
-  });
-  return result;
-}
-
 recursivelySetTemplateModel(element, model, [delegate]) {
   for (var node in element.queryAll('*')) {
     if (node.isTemplate) {
@@ -39,7 +30,7 @@ dispatchEvent(type, target) {
   target.dispatchEvent(new Event(type, cancelable: false));
 }
 
-class FooBarModel extends ObservableBase {
+class FooBarModel extends Observable {
   @observable var foo;
   @observable var bar;
 
@@ -47,7 +38,7 @@ class FooBarModel extends ObservableBase {
 }
 
 @reflectable
-class FooBarNotifyModel extends ChangeNotifierBase implements FooBarModel {
+class FooBarNotifyModel extends ChangeNotifier implements FooBarModel {
   var _foo;
   var _bar;