- Remove the unique objects used as slots since we decided 'null' was
fine after all
- Rename 'slot' to 'newSlot' when it's used as an argument to change the
_slot field, to clarify which variable has the newer value
- Remove the RenderObject registry since we'll do listeners a different
way. This also removes handleEvent for the same reason.
- Remove the TODOs for mount/unmount becoming didMount/didUnmount since
the methods do in fact do the mounting/unmounting.
In the old world, we had two ways to bind a Widget tree to a
RenderObject node, one way for RenderView and one mostly untested way
for other cases (it's only tested by the spinning_mixed.dart demo). For
fn3, I made these the same code path.
This patch also introduces GlobalKey, though the GlobalKey logic isn't
hooked in yet.
This is Hello World in the new world:
```dart
import 'package:sky/src/fn3.dart';
void main() {
runApp(new Text('Hello World!'));
}
```
- I extracted the BuildScheduler into a separate binding.dart file.
- Various changes to expose private members that are needed by
binding.dart.
- Registering the render objects for event dispatch.
- Convert the tests to use the new binding mechanism.
This doesn't yet have a RenderView or event handling.
- move _uniqueChild earlier since a comment now mentions it earlier.
- reorder methods in Element to more closely reflect call order.
- change mount to be the place that sets the parent pointer, for consistency.
- make the lifecycleState a purely debug-time thing for consistency.
- make BuildableElement.unmount set dirty to false so that we won't
build unmounted objects.
- rename "updated" to "newWidget" for clarity.
- change how we unmount things so that the slot is reset up to a
RenderObjectElement, but not further, and don't reset the depth.
- adds dartdocs
- replaces config setter with didUpdateConfig() so that you can't replace
the config outside of the system
- renames didUnmount() with destroy().
- rename Component to StatelessComponent, ComponentConfiguration to
StatefulComponent
- move debug dump to end of file
- renamed _holder to _element
This patch contains a prototype of a new widget framework. In this framework,
Components can be reused in the tree as many times as the author desires. Also,
StatefulComponent is split into two pieces, a ComponentConfiguration and a
ComponentState. The ComponentConfiguration is created by the author and can be
reused as many times as desired. When mounted into the tree, the
ComponentConfiguration creates a ComponentState to hold the state for the
component. The state remains in the tree and cannot be reused.
