Use ASTVisitor as in new AST.

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

Index: compiler/java/com/google/dart/compiler/ast/DartContext.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartContext.java b/compiler/java/com/google/dart/compiler/ast/DartContext.java
deleted file mode 100644
index 07d6a0f28c5a7ff762f8869f4b1e7cb1c1bbdcfc..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/ast/DartContext.java
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright (c) 2011, 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;
-
-/**
- * The context in which a DartNode visitation occurs. This represents the set of
- * possible operations a DartVisitor subclass can perform on the currently
- * visited node.
- */
-public interface DartContext {
-
-  boolean canInsert();
-
-  boolean canRemove();
-
-  void insertAfter(DartVisitable node);
-
-  void insertBefore(DartVisitable node);
-
-  boolean isLvalue();
-
-  void removeMe();
-
-  void replaceMe(DartVisitable node);
-}