dart2js cleanup: remove unused imports and variables

pkg/compiler/lib/src/native/enqueue.dart

Index: pkg/compiler/lib/src/native/enqueue.dart
diff --git a/pkg/compiler/lib/src/native/enqueue.dart b/pkg/compiler/lib/src/native/enqueue.dart
index 03f3fc20e0d056fc030c2f037a3dbb808364507b..0a414f6aa43dd69aedd2b5d6a8cbce75dc4a243d 100644
--- a/pkg/compiler/lib/src/native/enqueue.dart
+++ b/pkg/compiler/lib/src/native/enqueue.dart
@@ -7,22 +7,20 @@ import 'dart:collection' show Queue;
 import '../common.dart';
 import '../common/backend_api.dart' show ForeignResolver;
 import '../common/registry.dart' show Registry;
-import '../common/resolution.dart' show Parsing, Resolution;
+import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../core_types.dart' show CoreTypes;
 import '../dart_types.dart';
-import '../enqueue.dart' show Enqueuer, ResolutionEnqueuer;
 import '../elements/elements.dart';
-import '../elements/modelx.dart'
-    show BaseClassElementX, ElementX, FunctionElementX, LibraryElementX;
+import '../elements/modelx.dart' show FunctionElementX;
+import '../enqueue.dart' show Enqueuer;
 import '../js_backend/backend_helpers.dart' show BackendHelpers;
 import '../js_backend/js_backend.dart';
 import '../js_emitter/js_emitter.dart' show CodeEmitterTask, NativeEmitter;
 import '../tokens/token.dart' show BeginGroupToken, Token;
-import '../tokens/token_constants.dart' as Tokens show EOF_TOKEN, STRING_TOKEN;
+import '../tokens/token_constants.dart' as Tokens show EOF_TOKEN;
 import '../tree/tree.dart';
-
 import 'behavior.dart';
 
 /**