10 files declare their use of DataTypePluginBase in Search API 8

AlteringValueTestDataType.php in tests/search_api_test/src/Plugin/search_api/data_type/AlteringValueTestDataType.php

BooleanDataType.php in src/Plugin/search_api/data_type/BooleanDataType.php

DateDataType.php in src/Plugin/search_api/data_type/DateDataType.php

DecimalDataType.php in src/Plugin/search_api/data_type/DecimalDataType.php

IntegerDataType.php in src/Plugin/search_api/data_type/IntegerDataType.php

NoUi.php in tests/search_api_test_no_ui/src/Plugin/search_api/data_type/NoUi.php

StringDataType.php in src/Plugin/search_api/data_type/StringDataType.php

TestDataType.php in tests/search_api_test/src/Plugin/search_api/data_type/TestDataType.php

TextDataType.php in src/Plugin/search_api/data_type/TextDataType.php

UnsupportedTestDataType.php in tests/search_api_test/src/Plugin/search_api/data_type/UnsupportedTestDataType.php