Remove backends.

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

Index: compiler/java/com/google/dart/compiler/backend/js/ast/CanBooleanEval.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/ast/CanBooleanEval.java b/compiler/java/com/google/dart/compiler/backend/js/ast/CanBooleanEval.java
deleted file mode 100644
index 8f4364d94f2e4f9121efd69d00a54a5253b6bfe7..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/backend/js/ast/CanBooleanEval.java
+++ /dev/null
@@ -1,15 +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;
-
-/**
- * An interface that describes the boolean evaluation of an expression.
- */
-public interface CanBooleanEval {
-
-  boolean isBooleanFalse();
-
-  boolean isBooleanTrue();
-}