Remove backends.

compiler/java/com/google/dart/compiler/backend/js/ast/JsVisitable.java

Index: compiler/java/com/google/dart/compiler/backend/js/ast/JsVisitable.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/ast/JsVisitable.java b/compiler/java/com/google/dart/compiler/backend/js/ast/JsVisitable.java
deleted file mode 100644
index 626648af8aecf48fbc8bb40b0e3a16d063141381..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/backend/js/ast/JsVisitable.java
+++ /dev/null
@@ -1,19 +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.backend.js.ast;
-
-/**
- * Abstracts the idea that a class can be traversed.
- */
-public interface JsVisitable {
-
-  /**
-   * Causes this object to have the visitor visit itself and its children.
-   * 
-   * @param visitor the visitor that should traverse this node
-   * @param ctx the context of an existing traversal
-   */
-  void traverse(JsVisitor visitor, JsContext ctx);
-}