Reversing the dependency between the scheduler and services layer

Summary

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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.

Context

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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.

Description of change

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

Migration guide

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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:

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

Code after migration:

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

Timeline

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Landed in version: 1.18.0
In stable release: 1.20

References

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API documentation:

Relevant PRs: