[examples] Add C++ RomiReference example (#2969)

Co-authored-by: Prateek Machiraju <prateek.machiraju@gmail.com>
Co-authored-by: sciencewhiz <sciencewhiz@users.noreply.github.com>

wpilibcExamples/src/main/cpp/examples/RomiReference/include/Constants.h

@@ -0,0 +1,19 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+/**
+ * The Constants header provides a convenient place for teams to hold robot-wide
+ * numerical or bool constants.  This should not be used for any other purpose.
+ *
+ * It is generally a good idea to place constants into subsystem- or
+ * command-specific namespaces within this header, which can then be used where
+ * they are needed.
+ */
+
+namespace DriveConstants {
+constexpr double kCountsPerRevolution = 1440.0;
+constexpr double kWheelDiameterInch = 2.75;
+}  // namespace DriveConstants