spu: fix ugly cast in filter chain (and unexport function)

include/vlc_filter.h

@@ -400,7 +400,7 @@ VLC_API block_t * filter_chain_AudioFilter( filter_chain_t *, block_t * );
  * \param p_chain pointer to filter chain
  * \param display_date of subpictures
  */
-VLC_API void filter_chain_SubSource( filter_chain_t *, mtime_t );
+void filter_chain_SubSource( filter_chain_t *, spu_t *, mtime_t );
 
 /**
  * Apply filter chain to subpictures.

src/libvlccore.sym

@@ -128,7 +128,6 @@ filter_chain_MouseFilter
 filter_chain_MouseEvent
 filter_chain_New
 filter_chain_Reset
-filter_chain_SubSource
 filter_chain_SubFilter
 filter_chain_VideoFilter
 filter_chain_VideoFlush

src/misc/filter_chain.c

@@ -335,16 +335,15 @@ block_t *filter_chain_AudioFilter( filter_chain_t *p_chain, block_t *p_block )
     return p_block;
 }
 
-void filter_chain_SubSource( filter_chain_t *p_chain,
+void filter_chain_SubSource( filter_chain_t *p_chain, spu_t *spu,
                              mtime_t display_date )
 {
     for( chained_filter_t *f = p_chain->first; f != NULL; f = f->next )
     {
         filter_t *p_filter = &f->filter;
         subpicture_t *p_subpic = p_filter->pf_sub_source( p_filter, display_date );
-        /* XXX I find that spu_t cast ugly */
         if( p_subpic )
-            spu_PutSubpicture( (spu_t*)p_chain->p_this, p_subpic );
+            spu_PutSubpicture( spu, p_subpic );
     }
 }
 

src/video_output/vout_subpictures.c

@@ -1441,7 +1441,7 @@ subpicture_t *spu_Render(spu_t *spu,
         free(chain_update);
     }
     /* Run subpicture sources */
-    filter_chain_SubSource(sys->source_chain, render_osd_date);
+    filter_chain_SubSource(sys->source_chain, spu, render_osd_date);
     vlc_mutex_unlock(&sys->source_chain_lock);
 
     static const vlc_fourcc_t chroma_list_default_yuv[] = {