Support enums in dart2js.

pkg/compiler/lib/src/resolution/signatures.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.
 
 part of resolution;
 
 /**
  * [SignatureResolver] resolves function signatures.
  */
 class SignatureResolver extends MappingVisitor<FormalElementX> {
@@ skipping 332 matching lines @@
       optionalParameterTypes = optionalParameterTypesBuilder.toLink()
           .toList(growable: false);
     }
     FunctionType type = new FunctionType(
         element.declaration,
         returnType,
         parameterTypes.toLink().toList(growable: false),
         optionalParameterTypes,
         namedParameters,
         namedParameterTypes);
-    return new FunctionSignatureX(parameters,
-                                  visitor.optionalParameters,
-                                  requiredParameterCount,
-                                  visitor.optionalParameterCount,
-                                  visitor.optionalParametersAreNamed,
-                                  orderedOptionalParameters,
-                                  type);
+    return new FunctionSignatureX(
+        requiredParameters: parameters,
+        optionalParameters: visitor.optionalParameters,
+        requiredParameterCount: requiredParameterCount,
+        optionalParameterCount: visitor.optionalParameterCount,
+        optionalParametersAreNamed: visitor.optionalParametersAreNamed,
+        orderedOptionalParameters: orderedOptionalParameters,
+        type: type);
   }
 
   DartType resolveTypeAnnotation(TypeAnnotation annotation) {
     DartType type = resolveReturnType(annotation);
     if (type.isVoid) {
       compiler.reportError(annotation, MessageKind.VOID_NOT_ALLOWED);
     }
     return type;
   }
 
   DartType resolveReturnType(TypeAnnotation annotation) {
     if (annotation == null) return const DynamicType();
     DartType result = resolver.resolveTypeAnnotation(annotation);
     if (result == null) {
       return const DynamicType();
     }
     return result;
   }
 }