Remove Signal class and use Future/.whenComplete instead.

tests/lib/async/event_helper.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 event_helper;
 
 import 'dart:async';
 
 class Event {
   void replay(StreamSink sink);
@@ skipping 94 matching lines @@
   }
 
   // Operations that only work when there is a subscription feeding the Events.
 
   /**
    * Pauses the subscription that feeds this [Events].
    *
    * Should only be used when there is a subscription. That is, after a
    * call to [subscribeTo].
    */
-  void pause([Signal resumeSignal]) {
+  void pause([Future resumeSignal]) {
     throw new StateError("Not capturing events.");
   }
 
   /** Resumes after a call to [pause]. */
   void resume() {
     throw new StateError("Not capturing events.");
   }
 
   /** Whether the underlying subscription has been paused. */
   bool get isPaused => false;
 
   /**
    * Sets an action to be called when this [Events] receives a 'done' event.
    */
   void onDone(void action()) {
      throw new StateError("Not capturing events.");
   }
 }
 
 class CaptureEvents extends Events {
   StreamSubscription subscription;
-  SignalCompleter onDoneSignal;
+  Completer onDoneSignal;
   bool unsubscribeOnError = false;
 
   CaptureEvents(Stream stream,
                 { bool unsubscribeOnError: false })
-      : onDoneSignal = new SignalCompleter() {
+      : onDoneSignal = new Completer() {
     this.unsubscribeOnError = unsubscribeOnError;
     subscription = stream.listen(add,
                                  onError: signalError,
                                  onDone: close,
                                  unsubscribeOnError: unsubscribeOnError);
   }
 
   void signalError(AsyncError error) {
     super.signalError(error);
-    if (unsubscribeOnError) onDoneSignal.complete();
+    if (unsubscribeOnError) onDoneSignal.complete(null);
   }
 
   void close() {
     super.close();
-    if (onDoneSignal != null) onDoneSignal.complete();
+    if (onDoneSignal != null) onDoneSignal.complete(null);
   }
 
-  void pause([Signal resumeSignal]) {
+  void pause([Future resumeSignal]) {
     subscription.pause(resumeSignal);
   }
 
   void resume() {
     subscription.resume();
   }
 
   bool get isPaused => subscription.isPaused;
 
   void onDone(void action()) {
-    onDoneSignal.signal.then(action);
+    onDoneSignal.future.whenComplete(action);
   }
 }