Effen: willUmount->didUnmount, allow setState after didUnmount

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 510 matching lines @@
     sw.stop();
     if (_shouldLogRenderDuration)
       print("Render took ${sw.elapsedMicroseconds} microseconds");
   } finally {
     _inRenderDirtyComponents = false;
   }
 }
 
 void _scheduleComponentForRender(Component c) {
   assert(!_inRenderDirtyComponents);
-  if (_inRenderDirtyComponents)
-    return;
-
   _dirtyComponents.add(c);
 
   if (!_renderScheduled) {
     _renderScheduled = true;
     new Future.microtask(_renderDirtyComponents);
   }
 }
 
 abstract class Component extends Node {
   bool _dirty = true; // components begin dirty because they haven't rendered.
   Node _rendered = null;
   bool _removed = false;
   final int _order;
   static int _currentOrder = 0;
   bool _stateful;
   static Component _currentlyRendering;
 
   Component({ Object key, bool stateful })
       : _stateful = stateful != null ? stateful : false,
         _order = _currentOrder + 1,
         super(key:key);
 
-  void willUnmount() {}
+  void didUnmount() {}
 
   void _remove() {
     assert(_rendered != null);
     assert(_root != null);
-    willUnmount();
     _rendered._remove();
     _rendered = null;
     _root = null;
     _removed = true;
+    didUnmount();
   }
 
   // TODO(rafaelw): It seems wrong to expose DOM at all. This is presently
   // needed to get sizing info.
   sky.Node getRoot() => _root;
 
   bool _sync(Node old, sky.Node host, sky.Node insertBefore) {
     Component oldComponent = old as Component;
 
     if (oldComponent == null || oldComponent == this) {
@@ skipping 57 matching lines @@
     var rendered = _rendered;
     while (rendered is Component) {
       rendered = rendered._rendered;
     }
     sky.Node root = rendered._root;
 
     _renderInternal(root.parentNode, root.nextSibling);
   }
 
   void setState(Function fn()) {
-    assert(_rendered != null); // cannot setState before mounting.
+    assert(_rendered != null || _removed); // cannot setState before mounting.
     _stateful = true;
     fn();
-    if (_currentlyRendering != this) {
+    if (!_removed && _currentlyRendering != this) {
       _dirty = true;
       _scheduleComponentForRender(this);
     }
   }
 
   Node render();
 }
 
 abstract class App extends Component {
   sky.Node _host = null;
   App() : super(stateful: true) {
     _host = sky.document.createElement('div');
     sky.document.appendChild(_host);
 
     new Future.microtask(() {
       Stopwatch sw = new Stopwatch()..start();
 
       _sync(null, _host, null);
       assert(_root is sky.Node);
 
       sw.stop();
       if (_shouldLogRenderDuration)
         print("Initial render: ${sw.elapsedMicroseconds} microseconds");
     });
   }
 }