Adding event type getter to EventStreamProvider.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 3ff88831fd47ef6083fa76cdfcaf56b576a36a3f..692977d356ac8e686aa89d5e81611e4f04f8ec64 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -30849,6 +30849,17 @@ class EventStreamProvider<T extends Event> {
   Stream<T> forTarget(EventTarget e, {bool useCapture: false}) {
     return new _EventStream(e, _eventType, useCapture);
   }
+
+  /**
+   * Gets the type of the event which this would listen for on the specified
+   * event target.
+   *
+   * The target is necessary because some browsers may use different event names
+   * for the same purpose and the target allows differentiating browser support.
+   */
+  String getEventType(EventTarget target) {
+    return _eventType;
+  }
 }
 
 /**
@@ -30864,6 +30875,10 @@ class _CustomEventStreamProvider<T extends Event>
   Stream<T> forTarget(EventTarget e, {bool useCapture: false}) {
     return new _EventStream(e, _eventTypeGetter(e), useCapture);
   }
+
+  String getEventType(EventTarget target) {
+    return _eventTypeGetter(target);
+  }
 }
 // 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