Implement call operator.

lib/compiler/implementation/enqueue.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.
 
 class EnqueueTask extends CompilerTask {
   final Enqueuer codegen;
   final Enqueuer resolution;
 
   String get name() => 'Enqueue';
 
@@ skipping 305 matching lines @@
     });
   }
 
   // TODO(ngeoffray): This should get a type.
   void registerIsCheck(Element element) {
     universe.isChecks.add(element);
   }
 
   void forEach(f(WorkItem work)) {
     while (!queue.isEmpty()) {
-      f(queue.removeLast());
+      do {
+        f(queue.removeLast());
+      } while (!queue.isEmpty());
+      // TODO(ahe): we shouldn't register the field closure invocations here.
+      registerFieldClosureInvocations();
     }
   }
 }