dart2js cps: 'is'-check directly against type 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 '../js_backend.dart';
 import '../../dart2jslib.dart';
 import '../../js_emitter/js_emitter.dart';
 import '../../js/js.dart' as js;
@@ skipping 157 matching lines @@
   }
 
   FunctionElement getAddRuntimeTypeInformation() {
     return _backend.getSetRuntimeTypeInfo();
   }
 
   FunctionElement getCheckSubtype() {
     return _backend.getCheckSubtype();
   }
 
+  FunctionElement getCheckSubtypeOfRuntime() {
+    return _backend.getCheckSubtypeOfRuntimeType();
+  }
+
   js.Expression getRuntimeTypeName(ClassElement cls) {
     return js.string(_namer.runtimeTypeName(cls));
   }
 
   int getTypeVariableIndex(TypeVariableType variable) {
     return RuntimeTypes.getTypeVariableIndex(variable.element);
   }
 
   bool needsSubstitutionForTypeVariableAccess(ClassElement cls) {
     ClassWorld classWorld = _compiler.world;
@@ skipping 29 matching lines @@
   }
 
   bool operatorEqHandlesNullArgument(FunctionElement element) {
     return _backend.operatorEqHandlesNullArgument(element);
   }
 
   bool hasStrictSubtype(ClassElement element) {
     return _compiler.world.hasAnyStrictSubtype(element);
   }
 }