Create a public interface for AST nodes and rename the implementation classes

pkg/analyzer/lib/dart/ast/visitor.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 analyzer.dart.ast.visitor;
 
 import 'dart:collection';
 
-import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/dart/ast/ast.dart';
 
 /**
  * An AST visitor that will recursively visit all of the nodes in an AST
  * structure, similar to [GeneralizingAstVisitor]. This visitor uses a
  * breadth-first ordering rather than the depth-first ordering of
  * [GeneralizingAstVisitor].
  *
  * Subclasses that override a visit method must either invoke the overridden
  * visit method or explicitly invoke the more general visit method. Failure to
  * do so will cause the visit methods for superclasses of the node to not be
@@ skipping 1855 matching lines @@
    * Initialize a newly created visitor to help the [outerVisitor].
    */
   _BreadthFirstChildVisitor(this.outerVisitor);
 
   @override
   Object visitNode(AstNode node) {
     outerVisitor._queue.add(node);
     return null;
   }
 }