Run DOM callbacks in the zone they are coming from.

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index d7c89dadd13fa16dd11020029ba99108c6e4ed12..106ac6ced036fa3c58623bc83249c3882f4702d1 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -7707,7 +7707,6 @@ class Document extends Node
   @DocsEditable()
   DocumentFragment createDocumentFragment() native "Document_createDocumentFragment_Callback";
 
-  /// Deprecated: use new Element.tag(tagName) instead.
   @DomName('Document.createElement')
   @DocsEditable()
   Element _createElement(String localName_OR_tagName, [String typeExtension]) native "Document_createElement_Callback";
@@ -30735,11 +30734,17 @@ class _EventStreamSubscription<T extends Event> extends StreamSubscription<T> {
   var _onData;
   final bool _useCapture;
 
-  _EventStreamSubscription(this._target, this._eventType, this._onData,
-      this._useCapture) {
+  _EventStreamSubscription(this._target, this._eventType, onData,
+      this._useCapture) : _onData = _wrapZone(onData) {
     _tryResume();
   }
 
+  static _wrapZone(callback) {
+    // For performance reasons avoid wrapping if we are in the root zone.
+    if (Zone.current == Zone.ROOT) return callback;
+    return Zone.current.bindUnaryCallback(callback, runGuarded: true);
+  }
+
   void cancel() {
     if (_canceled) return;
 
@@ -30758,7 +30763,7 @@ class _EventStreamSubscription<T extends Event> extends StreamSubscription<T> {
     // Remove current event listener.
     _unlisten();
 
-    _onData = handleData;
+    _onData = _wrapZone(handleData);
     _tryResume();
   }