[Effen] Add AnimatedComponent base class

sky/framework/fn.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 'dart:async';
 import 'dart:collection';
 import 'dart:sky' as sky;
 import 'reflect.dart' as reflect;
@@ skipping 627 matching lines @@
 }
 
 List<Component> _dirtyComponents = new List<Component>();
 Set<Component> _mountedComponents = new HashSet<Component>();
 Set<Component> _unmountedComponents = new HashSet<Component>();
 
 bool _buildScheduled = false;
 bool _inRenderDirtyComponents = false;
 
 void _notifyMountStatusChanged() {
-  _unmountedComponents.forEach((c) => c.didUnmount());
-  _mountedComponents.forEach((c) => c.didMount());
+  _unmountedComponents.forEach((c) => c._didUnmount());
+  _mountedComponents.forEach((c) => c._didMount());
   _mountedComponents.clear();
   _unmountedComponents.clear();
 }
 
 void _buildDirtyComponents() {
   Stopwatch sw;
   if (_shouldLogRenderDuration)
     sw = new Stopwatch()..start();
 
   try {
@@ skipping 33 matching lines @@
   bool _dirty = true;
 
   sky.Node get _host => _root.parentNode;
   sky.Node get _insertionPoint => _root == null ? _root : _root.nextSibling;
 
   Node _built;
   final int _order;
   static int _currentOrder = 0;
   bool _stateful;
   static Component _currentlyBuilding;
+  List<Function> _mountCallbacks;
+  List<Function> _unmountCallbacks;
+
+  void onDidMount(Function fn) {
+    if (_mountCallbacks == null)
+      _mountCallbacks = new List<Function>();
+
+    _mountCallbacks.add(fn);
+  }
+
+  void onDidUnmount(Function fn) {
+    if (_unmountCallbacks == null)
+      _unmountCallbacks = new List<Function>();
+
+    _unmountCallbacks.add(fn);
+  }
+
 
   Component({ Object key, bool stateful })
       : _stateful = stateful != null ? stateful : false,
         _order = _currentOrder + 1,
         super(key:key);
 
   Component.fromArgs(Object key, bool stateful)
       : this(key: key, stateful: stateful);
 
-  void didMount() {}
-  void didUnmount() {}
+  void _didMount() {
+    if (_mountCallbacks != null)
+      _mountCallbacks.forEach((fn) => fn());
+  }
+
+  void _didUnmount() {
+    if (_unmountCallbacks != null)
+      _unmountCallbacks.forEach((fn) => fn());
+  }
 
   // TODO(rafaelw): It seems wrong to expose DOM at all. This is presently
   // needed to get sizing info.
   sky.Node getRoot() => _root;
 
   void _remove() {
     assert(_built != null);
     assert(_root != null);
     _removeChild(_built);
     _built = null;
@@ skipping 83 matching lines @@
 
 abstract class App extends Component {
   sky.Node _host;
 
   App() : super(stateful: true) {
     _host = sky.document.createElement('div');
     sky.document.appendChild(_host);
     _scheduleComponentForRender(this);
   }
 }