replace request.node with request.target.containingNode in more situations

pkg/analysis_server/lib/src/services/completion/arglist_computer.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 services.completion.computer.dart.arglist;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/completion/local_declaration_visitor.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 
 /**
  * A computer for calculating `completion.getSuggestions` request results
  * when the cursor position is inside the arguments to a method call.
  */
 class ArgListComputer extends DartCompletionComputer {
   _ArgListSuggestionBuilder builder;
 
   @override
   bool computeFast(DartCompletionRequest request) {
-    builder = request.node.accept(new _ArgListAstVisitor(request));
+    builder =
+        request.target.containingNode.accept(new _ArgListAstVisitor(request));
     return builder == null;
   }
 
   @override
   Future<bool> computeFull(DartCompletionRequest request) {
     if (builder != null) {
-      return builder.compute(request.node);
+      return builder.compute(request.target.containingNode);
     }
     return new Future.value(false);
   }
 }
 
 /**
  * A visitor for determining whether an argument list suggestion is needed
  * and instantiating the builder to create the suggestion.
  */
 class _ArgListAstVisitor
@@ skipping 149 matching lines @@
       if (id != null) {
         String name = id.name;
         if (name != null && name.length > 0) {
           return name;
         }
       }
     }
     return 'dynamic';
   }
 }