Converted Observatory class-tree element

runtime/observatory/tests/observatory_ui/mocks/repositories/script.dart

 // Copyright (c) 2016, 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 mocks;
 
+typedef Future<M.Script> ScriptRepositoryMockCallback(String id);
+
 class ScriptRepositoryMock implements M.ScriptRepository {
-  final Map<String, M.Script> scripts;
+  final ScriptRepositoryMockCallback _get;
 
-  bool _invoked = false;
-  bool get invoked => _invoked;
+  ScriptRepositoryMock({ScriptRepositoryMockCallback getter})
+    : _get = getter;
 
-  ScriptRepositoryMock(this.scripts);
-
-  Future<M.Script> get(String id) async {
-    _invoked = true;
-    return scripts[id];
+  Future<M.Script> get(String id){
+    if (_get != null) {
+      return _get(id);
+    }
+    return new Future.value(null);
   }
 }