add class dragdrop

include/nana/gui/dragdrop.hpp

@@ -31,7 +31,7 @@ namespace nana
 		simple_dragdrop(simple_dragdrop&&) = delete;
 		simple_dragdrop& operator=(simple_dragdrop&&) = delete;
 	public:
-		simple_dragdrop(window drag_wd);
+		simple_dragdrop(window source);
 		~simple_dragdrop();
 
 		/// Sets a condition that determines whether the drag&drop can start
@@ -40,6 +40,26 @@ namespace nana
 	private:
 		implementation* const impl_;
 	};
+
+	class dragdrop
+	{
+		struct implementation;
+
+		dragdrop(const dragdrop&) = delete;
+		dragdrop& operator=(const dragdrop&) = delete;
+
+		dragdrop(dragdrop&&) = delete;
+		dragdrop& operator=(dragdrop&&) = delete;
+	public:
+		dragdrop(window source);
+		~dragdrop();
+
+		void condition(std::function<bool()> predicate_fn);
+
+		void make_data(std::function<void()> generator);
+	private:
+		implementation* const impl_;
+	};
 }
 
 #endif