Get halsim_gazebo building again (#1201)

simulation/halsim_gazebo/src/main/native/include/GazeboEncoder.h

@@ -0,0 +1,32 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2014-2018 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include "HALSimGazebo.h"
+#include "simulation/gz_msgs/msgs.h"
+
+class GazeboEncoder {
+ public:
+  GazeboEncoder(int index, HALSimGazebo* halsim);
+  void SetInitialized(bool value) { m_initialized = value; }
+  bool IsInitialized(void) { return m_initialized; }
+  void SetReverse(bool value) { m_reverse = value; }
+  void Control(const char* command);
+  void Listen(void);
+
+ private:
+  HALSimGazebo* m_halsim;
+  int m_index;
+  bool m_initialized;
+  bool m_reverse;
+
+  void Callback(const gazebo::msgs::ConstFloat64Ptr& msg);
+
+  gazebo::transport::PublisherPtr m_pub;
+  gazebo::transport::SubscriberPtr m_sub;
+};