remove another unneeded file, add contents to window

platform/scene.go

@@ -1,17 +0,0 @@
-package platform
-
-type Scene interface {
-	Name() string
-}
-
-type SceneCreator interface {
-	Create() error
-}
-
-type SceneAdvancer interface {
-	Advance() error
-}
-
-type SceneDestroyer interface {
-	Destroy() error
-}

platform/window.go

@@ -16,6 +16,22 @@ var (
 	ErrWindowNotExists = errors.New("no window has been created")
 )
 
+type Scene interface {
+	Name() string
+}
+
+type SceneCreator interface {
+	Create() error
+}
+
+type SceneAdvancer interface {
+	Advance() error
+}
+
+type SceneDestroyer interface {
+	Destroy() error
+}
+
 var windowState struct {
 	sdlWindow    *sdl.Window
 	sdlGlContext sdl.GLContext