dart2js cleanup: remove unused imports and variables

pkg/compiler/lib/src/js_emitter/model.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.new_js_emitter.model;
 
 import '../constants/values.dart' show ConstantValue;
 import '../deferred_load.dart' show OutputUnit;
 import '../elements/elements.dart' show Element;
-import '../js/js.dart' as js
-    show Expression, Literal, Name, Statement, TokenFinalizer;
-
+import '../js/js.dart' as js show Expression, Name, Statement, TokenFinalizer;
 import 'js_emitter.dart' show MetadataCollector;
 
 class Program {
   final List<Fragment> fragments;
   final List<Holder> holders;
   final bool outputContainsConstantList;
   final bool needsNativeSupport;
   final bool hasIsolateSupport;
 
   /// A map from load id to the list of fragments that need to be loaded.
@@ skipping 504 matching lines @@
             functionType: functionType);
 
   bool get isStatic => true;
 }
 
 class StaticStubMethod extends StubMethod implements StaticMethod {
   Holder holder;
   StaticStubMethod(js.Name name, this.holder, js.Expression code)
       : super(name, code);
 }