Rename the confusingly named "ContentNode" class to "TagNode".

sky/sdk/lib/framework/fn2.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.
 
 library fn;
 
 import 'app.dart';
 import 'dart:async';
 import 'dart:collection';
 import 'dart:mirrors';
@@ skipping 135 matching lines @@
     }
 
     assert(!node.mounted);
     node.setParent(this);
     node._sync(oldNode, slot);
     assert(node.root is RenderObject);
     return node;
   }
 }
 
-abstract class ContentNode extends UINode {
+// Descendants of TagNode provide a way to tag RenderObjectWrapper and
+// Component nodes with annotations, such as event listeners,
+// stylistic information, etc.
+abstract class TagNode extends UINode {
   UINode content;
 
-  ContentNode(UINode content, { Object key }) : this.content = content, super(key: key);
+  TagNode(UINode content, { Object key }) : this.content = content, super(key: key);
 
   void _sync(UINode old, dynamic slot) {
-    UINode oldContent = old == null ? null : (old as ContentNode).content;
+    UINode oldContent = old == null ? null : (old as TagNode).content;
     content = syncChild(content, oldContent, slot);
     assert(content.root != null);
     root = content.root;
   }
 
   void remove() {
     if (content != null)
       removeChild(content);
     super.remove();
   }
 }
 
-class ParentDataNode extends ContentNode {
+class ParentDataNode extends TagNode {
   final ParentData parentData;
 
   ParentDataNode(UINode content, this.parentData, { Object key }): super(content, key: key);
 }
 
 typedef void GestureEventListener(sky.GestureEvent e);
 typedef void PointerEventListener(sky.PointerEvent e);
 typedef void EventListener(sky.Event e);
 
-class EventListenerNode extends ContentNode  {
+class EventListenerNode extends TagNode  {
   final Map<String, sky.EventListener> listeners;
 
   static Map<String, sky.EventListener> _createListeners({
     EventListener onWheel,
     GestureEventListener onGestureFlingCancel,
     GestureEventListener onGestureFlingStart,
     GestureEventListener onGestureScrollStart,
     GestureEventListener onGestureScrollUpdate,
     GestureEventListener onGestureTap,
     GestureEventListener onGestureTapDown,
@@ skipping 878 matching lines @@
     assert(root.parent is RenderView);
   }
 }
 
 class Text extends Component {
   Text(this.data) : super(key: '*text*');
   final String data;
   bool get interchangeable => true;
   UINode build() => new Paragraph(text: data);
 }