Introduce boot.js: this finally makes it possible to load and run Todomvc

lib/observe.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.
 
 /**
  * Helpers for observable objects.
  * Intended for use with `package:mdv_observe`.
  */
 library polymer.observe;
 
 import 'dart:async';
 // TODO(jmesserly): PathObserver should be in mdv_observe.
 import 'dart:html' show PathObserver;
 import 'package:observe/observe.dart';
 
-/**
- * Use `@observable` to make a property observable.
- * The overhead will be minimal unless they are actually being observed.
- */
-const observable = const _ObservableAnnotation();
-
-/**
- * The type of the `@observable` annotation.
- *
- * Library private because you should be able to use the [observable] field
- * to get the one and only instance. We could make it public though, if anyone
- * needs it for some reason.
- */
-class _ObservableAnnotation {
-  const _ObservableAnnotation();
-}
-
 // Inspired by ArrayReduction at:
 // https://raw.github.com/rafaelw/ChangeSummary/master/util/array_reduction.js
 // The main difference is we support anything on the rich Dart Iterable API.
 
 const _VALUE = const Symbol('value');
 
 /**
  * Forwards an observable property from one object to another. For example:
  *
  *     class MyModel extends ObservableBase {
@@ skipping 71 matching lines @@
 
   void _reduce() {
     _scheduled = false;
     _value = _observers.map((o) => o.value);
     notifyChange(new PropertyChangeRecord(_VALUE));
   }
 
   void _scheduleReduce(_) {
     if (_scheduled) return;
     _scheduled = true;
-    queueChangeRecords(_reduce);
+    runAsync(_reduce);
   }
 
   _observeItems(int lengthAdjust) {
     if (lengthAdjust > 0) {
       for (int i = 0; i < lengthAdjust; i++) {
         int len = _observers.length;
         var pathObs = new PathObserver(list, '$len.$_itemPath');
-        _subs.add(pathObs.values.listen(_scheduleReduce));
+        _subs.add(pathObs.bindSync(_scheduleReduce));

[Jennifer Messerly, 2013/07/27 02:18:44]

this should be:

  pathObs.changes.listen(_scheduleReduce);

... so it won't schedule if not needed. bindSync will pass the value
immediately.

[Siggi Cherem (dart-lang), 2013/07/30 00:10:29]

Done. Thanks, I saw 'values' went away, but didn't realize that it was replaced
by 'changes'.

         _observers.add(pathObs);
       }
     } else if (lengthAdjust < 0) {
       for (int i = 0; i < -lengthAdjust; i++) {
         _subs.removeLast().cancel();
       }
       int len = _observers.length;
       _observers.removeRange(len + lengthAdjust, len);
     }
   }
 
   setValueWorkaround(key, value) {}

[Jennifer Messerly, 2013/07/27 02:18:44]

these 2 lines be removed

[Siggi Cherem (dart-lang), 2013/07/30 00:10:29]

Done.

   getValueWorkaround(key) => key == _VALUE ? value : null;
 }