Reversing the dependency between the scheduler and services layer

The services layer now depends on the scheduler layer. Previously, the opposite was true. This may affect you if you have defined custom bindings overriding Flutter's SchedulerBinding or ServicesBinding.

Prior to this change, the scheduler layer was dependent on the services layer. This change reverses the dependency chain and allows the services layer to make use of the scheduling primitives in the scheduler layer. For example, services in the services layer can now schedule tasks by using SchedulerBinding.scheduleTask.

The change only affects users who are defining their own custom bindings based on Flutter's SchedulerBinding and ServicesBinding.

Prior to this change, the ServiceBinding had to be defined before the SchedulerBinding. With this change, it is the other way around:

Code before migration:

class FooBinding extends BindingBase with ServicesBinding, SchedulerBinding {
 // ...
}

Code after migration:

class FooBinding extends BindingBase with SchedulerBinding, ServicesBinding {
 // ...
}

Landed in version: 1.18.0
In stable release: 1.20

API documentation:

• ServicesBinding
• SchedulerBinding

Relevant PRs:

• Reverse dependency between services and scheduler
• Revert bindings dependency workaround