Remove ObserveCentersBase base tag

Author: kidder

src/ControlSystem/Tags/SystemTags.hpp

@@ -62,19 +62,7 @@ struct WriteDataToDisk : db::SimpleTag {
   static type create_from_options(const type& option) { return option; }
 };
 
-/// \ingroup DataBoxTagsGroup
-/// \ingroup ControlSystemGroup
-/// DataBox tag for writing the centers of the horizons to disk.
-///
-/// This is controlled by the `control_system::OptionTags::WriteDataToDisk`
-/// option in the input file.
-struct ObserveCenters : ::ah::Tags::ObserveCentersBase, db::SimpleTag {
-  using type = bool;
-  using option_tags = tmpl::list<OptionTags::WriteDataToDisk>;
-
-  static constexpr bool pass_metavariables = false;
-  static type create_from_options(const type& option) { return option; }
-};
+using ObserveCenters = ah::Tags::ObserveCenters;
 
 /// \ingroup DataBoxTagsGroup
 /// \ingroup ControlSystemGroup

src/ParallelAlgorithms/ApparentHorizonFinder/Callbacks/ObserveCenters.hpp

@@ -88,7 +88,7 @@ struct ObserveCenters {
         "DataBox must contain ylm::Tags::EuclideanAreaElement<Frame>");
 
     // Only print the centers if we want to.
-    if (not Parallel::get<ah::Tags::ObserveCentersBase>(cache)) {
+    if (not Parallel::get<ah::Tags::ObserveCenters>(cache)) {
       return;
     }
 

src/ParallelAlgorithms/ApparentHorizonFinder/Tags.hpp

@@ -14,8 +14,12 @@
 #include "IO/Logging/Verbosity.hpp"
 #include "ParallelAlgorithms/ApparentHorizonFinder/OptionTags.hpp"
 #include "ParallelAlgorithms/ApparentHorizonFinder/Storage.hpp"
+#include "Utilities/TMPL.hpp"
 
 /// \cond
+namespace control_system::OptionTags {
+struct WriteDataToDisk;
+}  // namespace control_system::OptionTags
 class FastFlow;
 namespace ylm {
 template <typename Frame>
@@ -122,16 +126,13 @@ struct FailedInterpolationIterations : db::SimpleTag {
   using type = size_t;
 };
 
-/// Base tag for whether or not to write the centers of the horizons to disk.
-/// Most likely to be used in the `ObserveCenters` post horizon find callback
-///
-/// Other things can control whether the horizon centers are output by defining
-/// their own simple tag from this base tag.
-struct ObserveCentersBase : db::BaseTag {};
-
 /// Simple tag for whether to write the centers of the horizons to disk.
 /// Currently this tag is not creatable by options
-struct ObserveCenters : ObserveCentersBase, db::SimpleTag {
+struct ObserveCenters : db::SimpleTag {
   using type = bool;
+  using option_tags = tmpl::list<control_system::OptionTags::WriteDataToDisk>;
+
+  static constexpr bool pass_metavariables = false;
+  static type create_from_options(const type& option) { return option; }
 };
 }  // namespace ah::Tags

tests/Unit/ParallelAlgorithms/ApparentHorizonFinder/Test_Tags.cpp

@@ -53,7 +53,5 @@ SPECTRE_TEST_CASE("Unit.ApparentHorizonFinder.Tags",
       "PreviousIterationStrahlkorper");
   TestHelpers::db::test_simple_tag<ah::Tags::FailedInterpolationIterations>(
       "FailedInterpolationIterations");
-  TestHelpers::db::test_base_tag<ah::Tags::ObserveCentersBase>(
-      "ObserveCentersBase");
   TestHelpers::db::test_simple_tag<ah::Tags::ObserveCenters>("ObserveCenters");
 }