Forget closure classes.

dart/sdk/lib/_internal/compiler/implementation/closure.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 closureToClassMapper;
 
 import "elements/elements.dart";
 import "dart2jslib.dart";
 import "dart_types.dart";
 import "js_backend/js_backend.dart" show JavaScriptBackend;
@@ skipping 84 matching lines @@
     Universe universe = compiler.enqueuer.codegen.universe;
     universe.instantiatedTypes
         ..remove(cls.rawType)
         ..remove(cls.thisType);
     universe.instantiatedClasses.remove(cls);
     cls.forEachLocalMember((Element e) {
       universe.closurizedMembers.remove(e);
       universe.fieldSetters.remove(e);
       universe.fieldGetters.remove(e);
     });
+    compiler.enqueuer.codegen.seenClasses.remove(cls);
   }
 }
 
 /// Common interface for [BoxFieldElement] and [ClosureFieldElement] as
 /// non-elements.
 abstract class CapturedVariable {}
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // find a more general solution.
 class ClosureFieldElement extends ElementX
@@ skipping 916 matching lines @@
 
   String get name => typeVariable.name;
 
   int get hashCode => typeVariable.hashCode;
 
   bool operator ==(other) {
     if (other is! TypeVariableLocal) return false;
     return typeVariable == other.typeVariable;
   }
 }