AP_OpticalFlow: pass mavlink_message_t by const reference

libraries/AP_OpticalFlow/AP_OpticalFlow_MAV.cpp

@@ -86,10 +86,10 @@ void AP_OpticalFlow_MAV::update(void)
 }
 
 // handle OPTICAL_FLOW mavlink messages
-void AP_OpticalFlow_MAV::handle_msg(const mavlink_message_t *msg)
+void AP_OpticalFlow_MAV::handle_msg(const mavlink_message_t &msg)
 {
     mavlink_optical_flow_t packet;
-    mavlink_msg_optical_flow_decode(msg, &packet);
+    mavlink_msg_optical_flow_decode(&msg, &packet);
 
     // record time message was received
     // ToDo: add jitter correction

libraries/AP_OpticalFlow/AP_OpticalFlow_MAV.h

@@ -16,7 +16,7 @@ public:
     void update(void) override;
 
     // get update from mavlink
-    void handle_msg(const mavlink_message_t *msg) override;
+    void handle_msg(const mavlink_message_t &msg) override;
 
     // detect if the sensor is available
     static AP_OpticalFlow_MAV *detect(OpticalFlow &_frontend);

libraries/AP_OpticalFlow/OpticalFlow.cpp

@@ -164,7 +164,7 @@ void OpticalFlow::update(void)
     _flags.healthy = (AP_HAL::millis() - _last_update_ms < 500);
 }
 
-void OpticalFlow::handle_msg(const mavlink_message_t *msg)
+void OpticalFlow::handle_msg(const mavlink_message_t &msg)
 {
     // exit immediately if not enabled
     if (!enabled()) {

libraries/AP_OpticalFlow/OpticalFlow.h

@@ -66,7 +66,7 @@ public:
     void update(void);
 
     // handle optical flow mavlink messages
-    void handle_msg(const mavlink_message_t *msg);
+    void handle_msg(const mavlink_message_t &msg);
 
     // quality - returns the surface quality as a measure from 0 ~ 255
     uint8_t quality() const { return _state.surface_quality; }

libraries/AP_OpticalFlow/OpticalFlow_backend.h

@@ -36,7 +36,7 @@ public:
     virtual void update() = 0;
 
     // handle optical flow mavlink messages
-    virtual void handle_msg(const mavlink_message_t *msg) {}
+    virtual void handle_msg(const mavlink_message_t &msg) {}
 
 protected:
     // access to frontend