Let completers complete in the zone they were constructed in.

sdk/lib/async/future_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.
 
 part of dart.async;
 
 deprecatedFutureValue(_FutureImpl future) =>
   future._isComplete ? future._resultOrListeners : null;
 
 abstract class _Completer<T> implements Completer<T> {
   final Future<T> future;

[Anders Johnsen, 2013/07/05 17:10:50]

It's okay to type this _FutureImpl, and then avoid the casts in the methods, as
this is not exposed (it's the private _Completer).

[floitsch, 2013/07/05 18:08:19]

I think I once had a _FutureImpl here, but Lasse asked me to change it.

[Lasse Reichstein Nielsen, 2013/07/05 18:49:43]

The argument was that is that the field is public, and I want it to match the
signature of Completer.

It may be irrelevant, since both this class and _FutureImpl are private, so it's
not like you can see a difference without mirrors, and with mirrors you can see
everything anyway.

   bool _isComplete = false;
+  final _Zone _zone = _Zone.current.fork();
 
   _Completer() : future = new _FutureImpl<T>() {

[Anders Johnsen, 2013/07/05 17:10:50]

So Future have a Zone too, so why not just use that zone? As it's constructed
just like here, they'll follow each other (actually be precisely the same)?

[floitsch, 2013/07/05 18:08:19]

Right...
No need for Zones in the completer. Removed.

[Lasse Reichstein Nielsen, 2013/07/05 18:49:43]

My interpretation too. Can't you just use future._zone?

[floitsch, 2013/07/05 18:51:46]

Completer.zone is already removed.

     _FutureImpl futureImpl = future;
+    _zone.expectCallback();
     futureImpl._zone.expectCallback();
   }
 
   void _setFutureValue(T value);
   void _setFutureError(error);
 
   void complete([T value]) {
     if (_isComplete) throw new StateError("Future already completed");
     _isComplete = true;
     _FutureImpl futureImpl = future;
+    _zone.cancelCallbackExpectation();
     futureImpl._zone.cancelCallbackExpectation();
     _setFutureValue(value);
   }
 
   void completeError(Object error, [Object stackTrace = null]) {
     if (_isComplete) throw new StateError("Future already completed");
     _isComplete = true;
     if (stackTrace != null) {
       // Force the stack trace onto the error, even if it already had one.
       _attachStackTrace(error, stackTrace);
     }
     _FutureImpl futureImpl = future;
-    if (futureImpl._inSameErrorZone(_Zone.current)) {
+    if (futureImpl._inSameErrorZone(_zone)) {

[Anders Johnsen, 2013/07/05 17:10:50]

futureImpl._zone and below?

[floitsch, 2013/07/05 18:08:19]

Actually it must be the same zone now, so I could remove the test.

+      _zone.cancelCallbackExpectation();
       futureImpl._zone.cancelCallbackExpectation();
       _setFutureError(error);
     } else {
-      _Zone.current.handleUncaughtError(error);
+      _zone.cancelCallbackExpectation();
+      _zone.handleUncaughtError(error);
     }
   }
 
   bool get isCompleted => _isComplete;
 }
 
 class _AsyncCompleter<T> extends _Completer<T> {
   void _setFutureValue(T value) {
     _FutureImpl future = this.future;
     runAsync(() { future._setValue(value); });
@@ skipping 600 matching lines @@
           _setError(error);
         }, onError: _setError);
         return;
       }
     } catch (e, s) {
       error = _asyncError(e, s);
     }
     _setError(error);
   }
 }