add mask

src/a2.h

@@ -3,10 +3,14 @@
 #include <vector>
 
 #include "bounding_box.h"
+#include "frame.h"
+#include "mask.h"
 
 namespace freling {
 
-// The normal signature for this function should be:
+std::vector<BoundingBox> A2(const Frame& frame, const Mask& mask);
+
+// The normal signature for this function is the one above:
 // std::vector<BoundingBox> A2(const Frame& regions);
 // However, since we are mocking this algorithm we just need to fulfill this
 // constraint: "We assume for the sake of simplicity, that no bounding boxe