Cleanup registration of closures

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, 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 js_backend.backend;
 
 import 'dart:async' show Future;
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 
@@ skipping 942 matching lines @@
       reporter.reportErrorMessage(
           node, MessageKind.WRONG_ARGUMENT_FOR_JS_INTERCEPTOR_CONSTANT);
     }
     // No native behavior for this call.
     return null;
   }
 
   bool isComplexNoSuchMethod(FunctionElement element) =>
       noSuchMethodRegistry.isComplex(element);
 
-  bool methodNeedsRti(FunctionElement function) {
-    return rtiNeed.methodNeedsRti(function);
-  }
-
   CodegenEnqueuer get codegenEnqueuer => compiler.enqueuer.codegen;
 
   /// Creates an [Enqueuer] for code generation specific to this backend.
   CodegenEnqueuer createCodegenEnqueuer(CompilerTask task, Compiler compiler) {
     return new CodegenEnqueuer(
         task, this, compiler.options, const TreeShakingEnqueuerStrategy());
   }
 
   WorldImpact codegen(CodegenWorkItem work) {
     Element element = work.element;
@@ skipping 678 matching lines @@
     return _backend.defaultSuperclass(element);
   }
 
   @override
   bool isNativeClass(ClassEntity element) =>
       _backend.nativeData.isNativeClass(element);
 
   @override
   bool isForeign(Element element) => _backend.isForeign(element);
 }