Issue #2975503: allow FieldConfigInterface::setDefaultValueCallback() to accept a callback in service notation

core/lib/Drupal/Core/Field/BaseFieldDefinition.php

@@ -439,7 +439,8 @@ public function getDefaultValueCallback() {
   public function getDefaultValue(FieldableEntityInterface $entity) {
     // Allow custom default values function.
     if ($callback = $this->getDefaultValueCallback()) {
-      $value = call_user_func($callback, $entity, $this);
+      $callable = \Drupal::service('callable_resolver')->getCallableFromDefinition($callback);
+      $value = call_user_func($callable, $entity, $this);
     }
     else {
       $value = $this->getDefaultValueLiteral();