Initial support for mixins in dartc.

compiler/java/com/google/dart/compiler/ast/ASTVisitor.java

 // Copyright (c) 2012, 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.
 
 package com.google.dart.compiler.ast;
 
 import java.util.List;
 
 /**
  * A visitor for abstract syntax tree.
@@ skipping 194 matching lines @@
     return visitNode(node);
   }
 
   public R visitFunctionExpression(DartFunctionExpression node) {
     return visitExpression(node);
   }
 
   public R visitFunctionTypeAlias(DartFunctionTypeAlias node) {
     return visitDeclaration(node);
   }
+  
+  public R visitClassTypeAlias(DartClassTypeAlias node) {
+    return visitDeclaration(node);
+  }
 
   public R visitIdentifier(DartIdentifier node) {
     return visitExpression(node);
   }
 
   public R visitIfStatement(DartIfStatement node) {
     return visitStatement(node);
   }
 
   public R visitImportCombinator(ImportCombinator node) {
@@ skipping 173 matching lines @@
   }
 
   public R visitNativeBlock(DartNativeBlock node) {
     return visitBlock(node);
   }
 
   public R visitRedirectConstructorInvocation(DartRedirectConstructorInvocation node) {
     return visitInvocation(node);
   }
 }