Description

Overhaul lifecycle management in GoogleMapsPlugin.

GoogleMapController is now uniformly driven by implementing DefaultLifecycleObserver. That observer is registered to a lifecycle passed via the new LifecycleProvider interface, which has 3 implementations:

1. For v2 plugin registration, GoogleMapsPlugin implements the interface and holds the lifecycle in a field, which is itself controlled by ActivityAware methods.
2. For v1 plugin registration, if the activity implements LifecycleOwner, it's lifecycle is used directly.
3. For v1 plugin registration, if the activity does not implement LifecycleOwner, a proxy lifecycle is created via ActivityLifecycleCallbacks.

I'm suspicious that there may still be a bug where a GoogleMapController instance can be shared across multiple activities and therefore leak the activity and lifecycle.

Related Issues

• Fixes [google_maps_flutter] getActivityHashCode in GoogleMapController.java might return -1 if the activity is in the background flutter#69128
• Works towards addressing [google_maps_flutter] Empty map when resuming from background on Android flutter#40284

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Breaking Change

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