HostDisplay: Add texture dumping/saving support

src/duckstation-sdl/opengl_host_display.h

@@ -3,8 +3,8 @@
 #include "common/gl/texture.h"
 #include "core/host_display.h"
 #include <SDL.h>
-#include <string>
 #include <memory>
+#include <string>
 
 class OpenGLHostDisplay final : public HostDisplay
 {
@@ -26,6 +26,8 @@ public:
                                                     bool dynamic) override;
   void UpdateTexture(HostDisplayTexture* texture, u32 x, u32 y, u32 width, u32 height, const void* data,
                      u32 data_stride) override;
+  bool DownloadTexture(const void* texture_handle, u32 x, u32 y, u32 width, u32 height, void* out_data,
+                       u32 out_data_stride) override;
 
   void SetVSync(bool enabled) override;