Roll polymer to 0.3.5

pkg/polymer/lib/src/events.dart

 // Copyright (c) 2013, 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.
 
 /// Code from declaration/events.js
 part of polymer;
 
 /// An extension of [polymer_expressions.PolymerExpressions] that adds support
 /// for binding events using `on-eventName` using [PolymerEventBindings].
 // TODO(jmesserly): the JS layering is a bit odd, with polymer-dev implementing
@@ skipping 71 matching lines @@
 
   prepareEventBinding(String path, String name, Node node) {
     if (!_hasEventPrefix(name)) return null;
 
     var eventType = _removeEventPrefix(name);
     var translated = _eventTranslations[eventType];
     eventType = translated != null ? translated : eventType;
 
     return (model, node, oneTime) {
       var handler = getEventHandler(null, node, path);
-      var sub = node.on[eventType].listen(handler);
+      _PolymerGestures.callMethod(
+          'addEventListener', [node, eventType, handler]);

[Siggi Cherem (dart-lang), 2014/08/13 23:00:26]

I think we need to bind handler to the current zone here.

[jakemac, 2014/08/14 18:00:49]

Ah nice good catch, I was just working on a bug that this fixed :).

 
       if (oneTime) return null;

[Siggi Cherem (dart-lang), 2014/08/13 23:00:26]

I know this is how it was before and how it in JS, but I'm surprised that this
is not done above the addEventListener call. looks like we would never remove
the listener. I presume it gets collected when the node is removed/detached, but
it makes me wonder a bit

[jakemac, 2014/08/14 18:00:49]

Would you be fine with us filing this as an investigation task in a separate
bug?

[Siggi Cherem (dart-lang), 2014/08/14 20:51:24]

sure thing

-      return new _EventBindable(sub, path);
+      return new _EventBindable(path, node, eventType, handler);
     };
   }
 }
 
 
 class _EventBindable extends Bindable {
-  StreamSubscription _sub;
   final String _path;
+  final Node _node;
+  final String _eventType;
+  final EventListener _handler;
 
-  _EventBindable(this._sub, this._path);
+  _EventBindable(this._path, this._node, this._eventType, this._handler);
 
   // TODO(rafaelw): This is really pointless work. Aside from the cost
   // of these allocations, NodeBind is going to setAttribute back to its
   // current value. Fixing this would mean changing the TemplateBinding
   // binding delegate API.
   get value => '{{ $_path }}';
 
   open(callback) => value;
 
   void close() {
-    if (_sub != null) {
-      _sub.cancel();
-      _sub = null;
-    }
+    _PolymerGestures.callMethod(
+        'removeEventListener', [_node, _eventType, _handler]);

[Siggi Cherem (dart-lang), 2014/08/13 23:00:26]

mmm... I'm not sure if js-interop guarantees that we get the same object when
serializing closures multiple times. If it doesn't, the removeEventListener
might be getting a reference that looks different than the one in the
addEventListener call, in which case the listener is never removed. We might
need to write some special tests to check for this.

[jakemac, 2014/08/14 18:00:49]

Could this be solved by jsifying the handler on our own before passing it in
(and keeping a reference to that same jsified callback to pass here)?

[Siggi Cherem (dart-lang), 2014/08/14 20:51:24]

I think that's possible, probably you can create a JsFunction object and use
that.

   }
 }
 
 
 /// Attribute prefix used for declarative event handlers.
 const _EVENT_PREFIX = 'on-';
 
 /// Whether an attribute declares an event.
 bool _hasEventPrefix(String attr) => attr.startsWith(_EVENT_PREFIX);
 
@@ skipping 28 matching lines @@
   return map;
 }();
 
 // Dart note: we need this function because we have additional renames JS does
 // not have. The JS renames are simply case differences, whereas we have ones
 // like doubleclick -> dblclick and stripping the webkit prefix.
 String _eventNameFromType(String eventType) {
   final result = _reverseEventTranslations[eventType];
   return result != null ? result : eventType;
 }