GoogleSignInWidget class

A widget that provides Google Sign-In functionality for all platforms.

The widget can manage its own authentication state, or you can provide an external controller for advanced use cases like sharing state across multiple widgets or integrating with state management solutions.

When controller is not provided, you must supply client and optionally onAuthenticated and onError callbacks. When controller is provided, those callbacks are handled by the controller itself.

Example with managed state:

GoogleSignInWidget(
  client: client,
  onAuthenticated: () => Navigator.push(...),
  onError: (error) => showSnackBar(...),
)

Example with external controller:

final controller = GoogleAuthController(
  client: client,
  onAuthenticated: ...,
);

GoogleSignInWidget(
  controller: controller,
)