Implement measurement using futures

client/html/src/EventTargetWrappingImplementation.dart

 // Copyright (c) 2011, 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.
 
-class _ListenerWrapper {
-  final EventListener raw;
-  final Function wrapped;
-  final String type;
-  final bool useCapture;
-
-  _ListenerWrapper(this.raw, this.wrapped, this.type, this.useCapture);
-}
-
 class EventsImplementation implements Events {
-  /* raw event target. */
+  /* Raw event target. */
   var _ptr;
 
   Map<String, EventListenerList> _listenerMap;
 
   EventsImplementation._wrap(this._ptr) {
     _listenerMap = <String, EventListenerList>{};
   }
 
   EventListenerList operator [](String type) {
     return _get(type.toLowerCase());
@@ skipping 25 matching lines @@
     _add(listener, useCapture);
     return this;
   }
 
   EventListenerList remove(EventListener listener, [bool useCapture = false]) {
     _remove(listener, useCapture);
     return this;
   }
 
   bool dispatch(Event evt) {
-    // TODO(jacobr): what is the correct behavior here?
+    // TODO(jacobr): what is the correct behavior here. We could alternately
+    // force the event to have the expected type.
     assert(evt.type == _type);
     return _ptr.dispatchEvent(LevelDom.unwrap(evt));
   }
 
   void _add(EventListener listener, bool useCapture) {
     _ptr.addEventListener(_type,
                           _findOrAddWrapper(listener, useCapture),
                           useCapture);
   }
 
   void _remove(EventListener listener, bool useCapture) {
     Function wrapper = _removeWrapper(listener, useCapture);
     if (wrapper !== null) {
       _ptr.removeEventListener(_type, wrapper, useCapture);
     }
   }
 
   Function _removeWrapper(EventListener listener, bool useCapture) {
     if (_wrappers === null) {
       return null;
     }
     for (int i = 0; i < _wrappers.length; i++) {
       _EventListenerWrapper wrapper = _wrappers[i];
-      if (wrapper.raw === listener
-          && wrapper.useCapture == useCapture) {
+      if (wrapper.raw === listener && wrapper.useCapture == useCapture) {
         // Order doesn't matter so we swap with the last element instead of
         // performing a more expensive remove from the middle of the list.
         if (i + 1 != _wrappers.length) {
           _wrappers[i] = _wrappers.removeLast();
         } else {
           _wrappers.removeLast();
         }
         return wrapper.wrapped;
       }
     }
     return null;
   }
 
   Function _findOrAddWrapper(EventListener listener, bool useCapture) {
     if (_wrappers === null) {
       _wrappers = <_EventListenerWrapper>[];
     } else {
       for (_EventListenerWrapper wrapper in _wrappers) {
         if (wrapper.raw === listener && wrapper.useCapture == useCapture) {
           return wrapper.wrapped;
         }
       }
     }
-    final wrapped = (e) => listener(LevelDom.wrapEvent(e));
+    final wrapped = (e) { listener(LevelDom.wrapEvent(e)); };
     _wrappers.add(new _EventListenerWrapper(listener, wrapped, useCapture));
     return wrapped;
   }
 }
 
 class EventTargetWrappingImplementation extends DOMWrapperBase implements EventTarget {
   Events _on;
 
   EventTargetWrappingImplementation._wrap(ptr) : super._wrap(ptr);
 
   Events get on() {
     if (_on === null) {
       _on = new EventsImplementation._wrap(_ptr);
     }
     return _on;
   }
 }