[commands] Refactor lambda-based commands to inherit FunctionalCommand (#4451)

wpilibNewCommands/src/main/native/include/frc2/command/InstantCommand.h

@@ -9,8 +9,8 @@
 
 #include <wpi/span.h>
 
-#include "frc2/command/CommandBase.h"
 #include "frc2/command/CommandHelper.h"
+#include "frc2/command/FunctionalCommand.h"
 
 namespace frc2 {
 /**
@@ -20,7 +20,7 @@ namespace frc2 {
  *
  * This class is provided by the NewCommands VendorDep
  */
-class InstantCommand : public CommandHelper<CommandBase, InstantCommand> {
+class InstantCommand : public CommandHelper<FunctionalCommand, InstantCommand> {
  public:
   /**
    * Creates a new InstantCommand that runs the given Runnable with the given
@@ -51,12 +51,5 @@ class InstantCommand : public CommandHelper<CommandBase, InstantCommand> {
    * only as a no-arg constructor to call implicitly from subclass constructors.
    */
   InstantCommand();
-
-  void Initialize() override;
-
-  bool IsFinished() final;
-
- private:
-  std::function<void()> m_toRun;
 };
 }  // namespace frc2