Extract imgcodecs module from highgui

modules/features2d/perf/perf_precomp.hpp

@@ -10,7 +10,7 @@
 #define __OPENCV_PERF_PRECOMP_HPP__
 
 #include "opencv2/ts.hpp"
-#include "opencv2/highgui.hpp"
+#include "opencv2/imgcodecs.hpp"
 #include "opencv2/features2d.hpp"
 
 #ifdef GTEST_CREATE_SHARED_LIBRARY

modules/features2d/test/test_descriptors_regression.cpp

@@ -40,7 +40,6 @@
 //M*/
 
 #include "test_precomp.hpp"
-#include "opencv2/highgui.hpp"
 
 using namespace std;
 using namespace cv;

modules/features2d/test/test_precomp.hpp

@@ -12,7 +12,7 @@
 #include "opencv2/ts.hpp"
 #include "opencv2/imgproc.hpp"
 #include "opencv2/features2d.hpp"
-#include "opencv2/highgui.hpp"
+#include "opencv2/imgcodecs.hpp"
 #include <iostream>
 
 #endif