[pkg:observe] Add support for explicit change notification, even on dirty-checked objects

[pkg:observe] Add support for explicit change notification, even on dirty-checked objects.

This is to fix warnings in Polymer.dart's TodoMVC example. Even though the objects extend ObservableMixin, they still have some computed fields that they notify manually. This seems like a scenario we should support, WDYT?

Also fixed a TODO about sending an unmodifiable list to the stream.

R=sigmund@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25531

[Siggi Cherem (dart-lang), 2013-07-26 15:53:14]

lgtm!

https://codereview.chromium.org/20631002/diff/2001/pkg/observe/lib/src/observ...
File pkg/observe/lib/src/observable.dart (right):

https://codereview.chromium.org/20631002/diff/2001/pkg/observe/lib/src/observ...
pkg/observe/lib/src/observable.dart:149: // Start with an manually notified
records (computed properties, etc),
an manually => a list of manually?

[Jennifer Messerly, 2013-07-26 18:14:43]

https://codereview.chromium.org/20631002/diff/2001/pkg/observe/lib/src/observ...
File pkg/observe/lib/src/observable.dart (right):

https://codereview.chromium.org/20631002/diff/2001/pkg/observe/lib/src/observ...
pkg/observe/lib/src/observable.dart:149: // Start with an manually notified
records (computed properties, etc),
On 2013/07/26 15:53:14, Siggi Cherem (dart-lang) wrote:
> an manually => a list of manually?

fixed. not sure what "an" was doing there.

[Jennifer Messerly, 2013-07-26 18:15:36]

Committed patchset #2 manually as r25531 (presubmit successful).