AP_WheelEncoder: remove empty constructors

libraries/AP_WheelEncoder/WheelEncoder_Quadrature.cpp

@@ -21,12 +21,6 @@
 
 extern const AP_HAL::HAL& hal;
 
-// constructor
-AP_WheelEncoder_Quadrature::AP_WheelEncoder_Quadrature(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state) :
-    AP_WheelEncoder_Backend(frontend, instance, state)
-{
-}
-
 // check if pin has changed and initialise gpio event callback
 void AP_WheelEncoder_Quadrature::update_pin(uint8_t &pin,
                                             uint8_t new_pin,

libraries/AP_WheelEncoder/WheelEncoder_Quadrature.h

@@ -23,7 +23,7 @@ class AP_WheelEncoder_Quadrature : public AP_WheelEncoder_Backend
 {
 public:
     // constructor
-    AP_WheelEncoder_Quadrature(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state);
+    using AP_WheelEncoder_Backend::AP_WheelEncoder_Backend;
 
     // update state
     void update(void) override;

libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.cpp

@@ -22,14 +22,10 @@
 
 extern const AP_HAL::HAL& hal;
 
-AP_WheelEncoder_SITL_Qaudrature::AP_WheelEncoder_SITL_Qaudrature(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state) :
-    AP_WheelEncoder_Backend(frontend, instance, state),
-    _sitl(AP::sitl())
-{
-}
-
 void AP_WheelEncoder_SITL_Qaudrature::update(void)
 {
+    const auto *_sitl = AP::sitl();
+
     // earth frame velocity of vehicle in vector form
     const Vector2f ef_velocity(_sitl->state.speedN, _sitl->state.speedE);
     // store current heading

libraries/AP_WheelEncoder/WheelEncoder_SITL_Quadrature.h

@@ -24,14 +24,12 @@ class AP_WheelEncoder_SITL_Qaudrature : public AP_WheelEncoder_Backend
 {
 public:
     // constructor
-    AP_WheelEncoder_SITL_Qaudrature(AP_WheelEncoder &frontend, uint8_t instance, AP_WheelEncoder::WheelEncoder_State &state);
+    using AP_WheelEncoder_Backend::AP_WheelEncoder_Backend;
 
     // update state
     void update(void) override;
 
 private:
-    SITL::SIM *_sitl; // pointer to SITL singleton
-
     int32_t  _distance_count; // distance count as number of encoder ticks
     uint32_t _total_count; // total number of encoder ticks
 };