AP_Logger: use singletons when logging camera information

libraries/AP_Logger/AP_Logger.h

@@ -246,9 +246,9 @@ public:
     void Write_Radio(const mavlink_radio_t &packet);
     void Write_Message(const char *message);
     void Write_MessageF(const char *fmt, ...);
-    void Write_CameraInfo(enum LogMessages msg, const AP_AHRS &ahrs, const Location &current_loc, uint64_t timestamp_us=0);
+    void Write_CameraInfo(enum LogMessages msg, const Location &current_loc, uint64_t timestamp_us=0);
-    void Write_Camera(const AP_AHRS &ahrs, const Location &current_loc, uint64_t timestamp_us=0);
+    void Write_Camera(const Location &current_loc, uint64_t timestamp_us=0);
-    void Write_Trigger(const AP_AHRS &ahrs, const Location &current_loc);
+    void Write_Trigger(const Location &current_loc);
     void Write_ESC(uint8_t id, uint64_t time_us, int32_t rpm, uint16_t voltage, uint16_t current, int16_t temperature, uint16_t current_tot);
     void Write_Attitude(AP_AHRS &ahrs, const Vector3f &targets);
     void Write_AttitudeView(AP_AHRS_View &ahrs, const Vector3f &targets);

libraries/AP_Logger/LogFile.cpp

@@ -543,8 +543,10 @@ void AP_Logger::Write_Radio(const mavlink_radio_t &packet)
 }
 
 // Write a Camera packet
-void AP_Logger::Write_CameraInfo(enum LogMessages msg, const AP_AHRS &ahrs, const Location &current_loc, uint64_t timestamp_us)
+void AP_Logger::Write_CameraInfo(enum LogMessages msg, const Location &current_loc, uint64_t timestamp_us)
 {
+    const AP_AHRS &ahrs = AP::ahrs();
+
     int32_t altitude, altitude_rel, altitude_gps;
     if (current_loc.relative_alt) {
         altitude = current_loc.alt+ahrs.get_home().alt;
@@ -578,15 +580,15 @@ void AP_Logger::Write_CameraInfo(enum LogMessages msg, const AP_AHRS &ahrs, cons
 }
 
 // Write a Camera packet
-void AP_Logger::Write_Camera(const AP_AHRS &ahrs, const Location &current_loc, uint64_t timestamp_us)
+void AP_Logger::Write_Camera(const Location &current_loc, uint64_t timestamp_us)
 {
-    Write_CameraInfo(LOG_CAMERA_MSG, ahrs, current_loc, timestamp_us);
+    Write_CameraInfo(LOG_CAMERA_MSG, current_loc, timestamp_us);
 }
 
 // Write a Trigger packet
-void AP_Logger::Write_Trigger(const AP_AHRS &ahrs, const Location &current_loc)
+void AP_Logger::Write_Trigger(const Location &current_loc)
 {
-    Write_CameraInfo(LOG_TRIGGER_MSG, ahrs, current_loc, 0);
+    Write_CameraInfo(LOG_TRIGGER_MSG, current_loc, 0);
 }
 
 // Write an attitude packet