Support `void` as generic argument.

pkg/compiler/lib/src/js_emitter/startup_emitter/emitter.dart

 // Copyright (c) 2015, 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.js_emitter.startup_emitter;
 
 import 'package:js_runtime/shared/embedded_names.dart'
     show JsBuiltin, METADATA, STATIC_FUNCTION_NAME_TO_CLOSURE, TYPES;
 
 import '../../common.dart';
@@ skipping 144 matching lines @@
 
       case JsBuiltin.rawRtiToJsConstructorName:
         return js.js.expressionTemplateFor("#.$typeNameProperty");
 
       case JsBuiltin.rawRuntimeType:
         return js.js.expressionTemplateFor("#.constructor");
 
       case JsBuiltin.createFunctionTypeRti:
         return _backend.rtiEncoder.templateForCreateFunctionType;
 
+      case JsBuiltin.isVoidRti:
+        return _backend.rtiEncoder.templateForIsVoidRti;
+
       case JsBuiltin.isSubtype:
         // TODO(floitsch): move this closer to where is-check properties are
         // built.
         String isPrefix = namer.operatorIsPrefix;
         return js.js.expressionTemplateFor("('$isPrefix' + #) in #.prototype");
 
       case JsBuiltin.isGivenTypeRti:
         return js.js.expressionTemplateFor('#.$typeNameProperty === #');
 
       case JsBuiltin.getMetadata:
@@ skipping 17 matching lines @@
     }
   }
 
   @override
   int generatedSize(OutputUnit unit) {
     Fragment key = _emitter.outputBuffers.keys
         .firstWhere((Fragment fragment) => fragment.outputUnit == unit);
     return _emitter.outputBuffers[key].length;
   }
 }