8 files declare their use of WorkflowState in Workflow 8

workflow.api.php in ./workflow.api.php

Hooks provided by the workflow module.

workflow.field.inc in ./workflow.field.inc

Defines a Workflow field, widget and formatter. (copied from list field).

workflow.module in ./workflow.module

Support workflows made up of arbitrary states.

WorkflowAccessRoleForm.php in modules/workflow_access/src/Form/WorkflowAccessRoleForm.php

WorkflowCleanupSettingsForm.php in modules/workflow_cleanup/src/Form/WorkflowCleanupSettingsForm.php

WorkflowDefaultFormatter.php in src/Plugin/Field/FieldFormatter/WorkflowDefaultFormatter.php

WorkflowItem.php in src/Plugin/Field/FieldType/WorkflowItem.php

WorkflowStateListBuilder.php in src/WorkflowStateListBuilder.php