Match existing expectation that delegate returns unwrapped values.

runtime/lib/mirrors_impl.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.
 
 // VM-specific implementation of the dart:mirrors library.
 
 import "dart:collection";
 
 final emptyList = new UnmodifiableListView([]);
 final emptyMap = new _UnmodifiableMapView({});
@@ skipping 461 matching lines @@
     if (_function == null) {
       _function = _computeFunction(reflectee);
     }
     return _function;
   }
 
   // TODO(12602): Remove this special case.
   delegate(Invocation invocation) {
     if (invocation.isMethod && (invocation.memberName == #call)) {
       return this.apply(invocation.positionalArguments,
-                        invocation.namedArguments);
+                        invocation.namedArguments).reflectee;
     }
     return super.delegate(invocation);
   }
 
   InstanceMirror apply(List<Object> positionalArguments,
                        [Map<Symbol, Object> namedArguments]) {
     // TODO(12602): When closures get an ordinary call method, this can be
     // replaced with
     //   return this.invoke(#call, positionalArguments, namedArguments);
     // and the native ClosureMirror_apply can be removed.
@@ skipping 1152 matching lines @@
     if (typeMirror == null) {
       typeMirror = makeLocalTypeMirror(key);
       _instanitationCache[key] = typeMirror;
       if (typeMirror is ClassMirror && !typeMirror._isGeneric) {
         _declarationCache[key] = typeMirror;
       }
     }
     return typeMirror;
   }
 }