fix findController for non-dart elements

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 34 matching lines @@
 }
 
 /// A mixin for a [BindingDelegate] to add Polymer event support.
 /// This is included in [PolymerExpressions].
 abstract class PolymerEventBindings {
   /// Finds the event controller for this node.
   Element findController(Node node) {
     while (node.parentNode != null) {
       if (node is Polymer && node.eventController != null) {
         return node.eventController;
+      } else if (node is Element) {
+        // If it is a normal element, js polymer element, or dart wrapper to a
+        // js polymer element, then we try js interop.
+        var eventController =
+            new JsObject.fromBrowserObject(node)['eventController'];
+        if (eventController != null) return eventController;
       }
       node = node.parentNode;
     }
     return node is ShadowRoot ? node.host : null;
   }
 
   EventListener getEventHandler(controller, target, String method) => (e) {
     if (controller == null || controller is! Polymer) {
       controller = findController(target);
     }
@@ skipping 98 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;
 }