Arglist `children:` default value gen fixes.

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart

 // Copyright (c) 2014, 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 test.services.completion.dart.util;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart' as protocol
     show Element, ElementKind;
@@ skipping 192 matching lines @@
     expect(element.parameters, isNull);
     expect(element.returnType, isNull);
     assertHasNoParameterInfo(cs);
     return cs;
   }
 
   CompletionSuggestion assertSuggestConstructor(String name,
       {int relevance: DART_RELEVANCE_DEFAULT,
       String importUri,
       int elemOffset,
-      String defaultArgListString}) {
+      String defaultArgListString,
+      List<int> defaultArgumentListTextRanges}) {
     CompletionSuggestion cs = assertSuggest(name,
         relevance: relevance,
         importUri: importUri,
         elemOffset: elemOffset,
-        defaultArgListString: defaultArgListString);
+        defaultArgListString: defaultArgListString,
+        defaultArgumentListTextRanges: defaultArgumentListTextRanges);
     protocol.Element element = cs.element;
     expect(element, isNotNull);
     expect(element.kind, equals(protocol.ElementKind.CONSTRUCTOR));
     int index = name.indexOf('.');
     expect(element.name, index >= 0 ? name.substring(index + 1) : '');
     return cs;
   }
 
   CompletionSuggestion assertSuggestEnum(String completion,
       {bool isDeprecated: false}) {
@@ skipping 403 matching lines @@
 
   @override
   void setUp() {
     super.setUp();
     index = createMemoryIndex();
     searchEngine =
         new SearchEngineImpl(index, (_) => new AstProviderForContext(context));
     contributor = createContributor();
   }
 }