Wrapping leaf nodes in non polymer elements

runtime/observatory/lib/src/elements/curly_block.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.
 
 library curly_block_element;
 
-import 'package:polymer/polymer.dart';
-import 'observatory_element.dart';
+import 'dart:async';
+import 'dart:html';
+import 'helpers/tag.dart';
 
-@CustomTag('curly-block')
-class CurlyBlockElement extends ObservatoryElement {
-  CurlyBlockElement.created() : super.created();
+class CurlyBlockToggleEvent {
+  final CurlyBlockElement control;
 
-  @observable bool expanded = false;
-  @observable bool busy = false;
-  @published var callback = null;
-  @published bool expand = false;
-  @published String expandKey;
+  CurlyBlockToggleEvent(this.control);
+}
 
-  void expandChanged(oldValue) {
-    expanded = expand;
+class CurlyBlockElement extends HtmlElement {
+  static final StyleElement _style = () {
+      var style = new StyleElement();
+      style.text = '.idle {'
+                   '  display: inline-block;'
+                   '  color: #0489c3;'
+                   '  cursor: pointer;'
+                   '}'
+                   '.busy {'
+                   '  display: inline-block;'
+                   '  color: white;'
+                   '  cursor: wait;'
+                   '}';
+      return style;
+  }();
+
+  static const tag = const Tag<CurlyBlockElement>('curly-block-wrapped');
+
+  bool expanded;
+  bool busy;
+
+  final StreamController<CurlyBlockToggleEvent> _onToggle =
+    new StreamController<CurlyBlockToggleEvent>();
+  Stream<CurlyBlockToggleEvent> get onToggle => _onToggle.stream;
+
+  factory CurlyBlockElement() {
+    return document.createElement(tag.name);
   }
 
-  void expandKeyChanged(oldValue) {
-    if (expandKey != null) {
-      var value = app.expansions[expandKey];
-      if (value != null) {
-        if (expanded != value) {
-          toggleExpand(null, null, null);
-        }
-      }
-    }
+  CurlyBlockElement.created() : super.created() {
+    createShadowRoot();
   }
 
-  void doneCallback() {
-    expanded = !expanded;
-    if (expandKey != null) {
-      app.expansions[expandKey] = expanded;
-    }
-    busy = false;
+  @override
+  void attached() {
+    super.attached();
+    render();
   }
 
-  void toggleExpand(var event, var b, var c) {
-    assert(callback == null || expand == false);
+  void toggle() {
+    expanded = !expanded;
+    _onToggle.add(new CurlyBlockToggleEvent(this));
+    render();
+  }
+
+  void render() {
+    List<Element> children = [
+      _style.clone(true),
+      new SpanElement()..text = '{'
+    ];
+    DivElement label = new DivElement()
+      ..classes = [busy ? 'busy' : 'idle']
+      ..innerHtml = expanded ?
+        '&nbsp;&nbsp;&#8863;&nbsp;&nbsp;' : '&nbsp;&nbsp;&#8862;&nbsp;&nbsp;';
     if (busy) {
-      return;
+      children.add(label);
+    } else {
+      children.add(new AnchorElement()
+        ..onClick.listen((_) { toggle(); })
+        ..children = [label]);
     }
-    busy = true;
-    if (callback != null) {
-      callback(!expanded, doneCallback);
-    } else {
-      doneCallback();
+    if (expanded) {
+      children.addAll([
+        new BRElement(),
+        new ContentElement()
+      ]);
     }
+    children.add(new SpanElement()..text = '}');
+    shadowRoot.children = children;
   }
 }