dart2js cleanup: remove unused imports and variables

pkg/compiler/lib/src/js_backend/codegen/glue.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 code_generator_dependencies;
 
-import '../backend_helpers.dart' show BackendHelpers;
-import '../js_backend.dart';
-
 import '../../common.dart';
 import '../../common/codegen.dart' show CodegenRegistry;
 import '../../compiler.dart' show Compiler;
 import '../../constants/values.dart';
-import '../../dart_types.dart' show DartType, TypeVariableType, InterfaceType;
+import '../../dart_types.dart' show DartType, TypeVariableType;
+import '../../elements/elements.dart';
 import '../../enqueue.dart' show CodegenEnqueuer;
-import '../../elements/elements.dart';
+import '../../js/js.dart' as js;
 import '../../js_emitter/js_emitter.dart';
-import '../../js/js.dart' as js;
 import '../../native/native.dart' show NativeBehavior;
+import '../../types/types.dart';
 import '../../universe/selector.dart' show Selector;
 import '../../world.dart' show ClassWorld;
-import '../../types/types.dart';
+import '../backend_helpers.dart' show BackendHelpers;
+import '../js_backend.dart';
 
 /// Encapsulates the dependencies of the function-compiler to the compiler,
 /// backend and emitter.
 // TODO(sigurdm): Should be refactored when we have a better feeling for the
 // interface.
 class Glue {
   final Compiler _compiler;
 
   CodegenEnqueuer get _enqueuer => _compiler.enqueuer.codegen;
 
@@ skipping 253 matching lines @@
   bool mayGenerateInstanceofCheck(DartType type) {
     return _backend.mayGenerateInstanceofCheck(type);
   }
 
   bool methodUsesReceiverArgument(FunctionElement function) {
     assert(isInterceptedMethod(function));
     ClassElement class_ = function.enclosingClass.declaration;
     return isInterceptorClass(class_) || isUsedAsMixin(class_);
   }
 }