Clean-up imports

pkg/analyzer/example/parser_driver.dart

 #!/usr/bin/env dart
 // Copyright (c) 2013, 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.
 
 import 'dart:io';
 
-import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 
 main(List<String> args) {
   print('working dir ${new File('.').resolveSymbolicLinksSync()}');
 
   if (args.length == 0) {
     print('Usage: parser_driver [files_to_parse]');
     exit(0);
@@ skipping 26 matching lines @@
     print('${node.runtimeType} : <"$node">');
     return super.visitNode(node);
   }
 }
 
 class _ErrorCollector extends AnalysisErrorListener {
   List<AnalysisError> errors;
   _ErrorCollector() : errors = new List<AnalysisError>();
   onError(error) => errors.add(error);
 }