Rename EventListenerNode to Listener

sky/sdk/lib/widgets/material_button.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'basic.dart';
 import 'button_base.dart';
 import 'ink_well.dart';
 import 'material.dart';
 
 enum MaterialButtonTheme { light, dark }
@@ skipping 23 matching lines @@
   }
 
   Color get color;
   int get level;
 
   Widget buildContent() {
     Widget contents = new Container(
       padding: new EdgeDims.symmetric(horizontal: 8.0),
       child: new Center(child: child) // TODO(ianh): figure out a way to compell the child to have gray text when disabled...
     );
-    return new EventListenerNode(
-      new Container(
+    return new Listener(
+      child: new Container(
         height: 36.0,
         constraints: new BoxConstraints(minWidth: 88.0),
         margin: new EdgeDims.all(8.0),
         child: new Material(
           child: enabled ? new InkWell(child: contents) : contents,
           level: level,
           color: color
         )
       ),
       onGestureTap: (_) { if (onPressed != null && enabled) onPressed(); }
     );
   }
 
 }