wined3d: Make the surface parameter to surface_get_gl_buffer() const.

dlls/wined3d/surface.c

@@ -2412,9 +2412,9 @@ void surface_set_compatible_renderbuffer(struct wined3d_surface *surface, struct
     checkGLcall("set_compatible_renderbuffer");
 }
 
-GLenum surface_get_gl_buffer(struct wined3d_surface *surface)
+GLenum surface_get_gl_buffer(const struct wined3d_surface *surface)
 {
-    struct wined3d_swapchain *swapchain = surface->container.u.swapchain;
+    const struct wined3d_swapchain *swapchain = surface->container.u.swapchain;
 
     TRACE("surface %p.\n", surface);
 

dlls/wined3d/wined3d_private.h

@@ -2107,7 +2107,7 @@ static inline GLuint surface_get_texture_name(struct wined3d_surface *surface,
 void surface_add_dirty_rect(struct wined3d_surface *surface, const WINED3DBOX *dirty_rect) DECLSPEC_HIDDEN;
 void surface_bind(struct wined3d_surface *surface, const struct wined3d_gl_info *gl_info, BOOL srgb) DECLSPEC_HIDDEN;
 HRESULT surface_color_fill(struct wined3d_surface *s, const RECT *rect, const WINED3DCOLORVALUE *color) DECLSPEC_HIDDEN;
-GLenum surface_get_gl_buffer(struct wined3d_surface *surface) DECLSPEC_HIDDEN;
+GLenum surface_get_gl_buffer(const struct wined3d_surface *surface) DECLSPEC_HIDDEN;
 BOOL surface_init_sysmem(struct wined3d_surface *surface) DECLSPEC_HIDDEN;
 void surface_internal_preload(struct wined3d_surface *surface, enum WINED3DSRGB srgb) DECLSPEC_HIDDEN;
 BOOL surface_is_offscreen(const struct wined3d_surface *surface) DECLSPEC_HIDDEN;