Problem/Motivation
FieldDefinitionInterfacegetDefaultValue() requires an entity. This means if we don't have an entity we can't know the default value of a field. This is problematic for #2283977: Create a new ConfigEntity type for storing bundle-specific customizations of base fields when creating a node type and it needs to discover the default value for base fields of a node.
Proposed resolution
Allow a null to be passed to the function?
Remaining tasks
Write patch and tests
User interface changes
None
API changes
Yes