Include DDC fixes to dart:html in the main version

tools/dom/src/EventStreamProvider.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.
 
 part of html;
 
 /**
  * A factory to expose DOM events as Streams.
  */
 class EventStreamProvider<T extends Event> {
@@ skipping 218 matching lines @@
   //     ? _wrapZone/*<Event, dynamic>*/(onData)
   //     : _wrapZone/*<Event, dynamic>*/((e) => onData(e as T))
   // In order to support existing tests which pass the wrong type of events but
   // use a more general listener, without causing as much slowdown for things
   // which are typed correctly.  But this currently runs afoul of restrictions
   // on is checks for compatibility with the VM.
   _EventStreamSubscription(
       this._target, this._eventType, void onData(T event), this._useCapture)
       : _onData = onData == null
             ? null
-            : _wrapZone/*<Event, dynamic>*/((e) => (onData as dynamic)(e)) {
+            : _wrapZone<Event, dynamic>((e) => (onData as dynamic)(e)) {

[vsm, 2017/05/24 13:11:49]

Feel free to skip for this CL as it's nothing you're changing.

The "onDart as dynamic" looks a bit dodgy here.  Given the types,

onData(e as T) 

or 

_wrapZone<T, dynamic>

might make more sense.

     _tryResume();
   }
 
   Future cancel() {
     if (_canceled) return null;
 
     _unlisten();
     // Clear out the target to indicate this is complete.
     _target = null;
     _onData = null;
@@ skipping 188 matching lines @@
         e, _eventTypeGetter(e), useCapture);
   }
 
   String getEventType(EventTarget target) {
     return _eventTypeGetter(target);
   }
 
   String get _eventType =>
       throw new UnsupportedError('Access type through getEventType method.');
 }