Remove backends.

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

Index: compiler/java/com/google/dart/compiler/backend/js/ast/JsRootScope.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/ast/JsRootScope.java b/compiler/java/com/google/dart/compiler/backend/js/ast/JsRootScope.java
deleted file mode 100644
index 25c50b2c9ad606a2a1683aa8e24bc39c27596d74..0000000000000000000000000000000000000000
--- a/compiler/java/com/google/dart/compiler/backend/js/ast/JsRootScope.java
+++ /dev/null
@@ -1,50 +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;
-
-import com.google.dart.compiler.backend.js.JsReservedIdentifiers;
-
-/**
- * The root scope is the parent of every scope. All identifiers in this scope
- * are not obfuscatable. This scope is prefilled with reserved global
- * JavaScript symbols.
- */
-public final class JsRootScope extends JsScope {
-
-  private final JsProgram program;
-
-  public JsRootScope(JsProgram program) {
-    super("Root");
-    this.program = program;
-  }
-
-  @Override
-  public JsProgram getProgram() {
-    return program;
-  }
-
-  @Override
-  protected JsName doCreateName(String ident, String shortIdent, String originalName) {
-    JsName name = super.doCreateName(ident, shortIdent, originalName);
-    name.setObfuscatable(false);
-    return name;
-  }
-
-  @Override
-  protected JsName findExistingNameNoRecurse(String ident) {
-    JsName name = super.findExistingNameNoRecurse(ident);
-    if (name == null) {
-      if (JsReservedIdentifiers.getReservedGlobalSymbols().contains(ident)) {
-        /*
-         * Lazily add JsNames for reserved identifiers.  Since a JsName for a reserved global symbol
-         * must report a legitimate enclosing scope, we can't simply have a shared set of symbol
-         * names.
-         */
-        name = doCreateName(ident, ident, ident);
-      }
-    }
-    return name;
-  }
-}