Fixed overlay update in directx vout.

IDirectDrawSurface2_UpdateOverlay may fails, in which case vlc should simply
retry later.
(cherry picked from commit d0606472d5a245ec89846d091f5280e51874ed96)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/video_output/msw/common.h

@@ -126,6 +126,7 @@ struct vout_display_sys_t
     bool   use_wallpaper;   /* show as desktop wallpaper ? */
 
     bool   use_overlay;     /* Are we using an overlay surface */
+    bool   restore_overlay;
 
     /* DDraw capabilities */
     bool            can_blit_fourcc;

modules/video_output/msw/directx.c

@@ -193,6 +193,7 @@ static int Open(vlc_object_t *object)
     sys->use_wallpaper = var_CreateGetBool(vd, "video-wallpaper");
     /* FIXME */
     sys->use_overlay = false;//var_CreateGetBool(vd, "overlay"); /* FIXME */
+    sys->restore_overlay = false;
     var_Create(vd, "directx-device", VLC_VAR_STRING | VLC_VAR_DOINHERIT);
 
     /* Initialisation */
@@ -284,6 +285,8 @@ static void Display(vout_display_t *vd, picture_t *picture)
                 DirectXUpdateOverlay(vd, NULL);
         }
     }
+    if (sys->restore_overlay)
+        DirectXUpdateOverlay(vd, NULL);
 
     /* */
     DirectXUnlock(picture);
@@ -378,6 +381,10 @@ static void Manage(vout_display_t *vd)
 
     if (ch_wallpaper)
         WallpaperChange(vd, wallpaper_requested);
+
+    /* */
+    if (sys->restore_overlay)
+        DirectXUpdateOverlay(vd, NULL);
 }
 
 /* */
@@ -1330,6 +1337,8 @@ static int DirectXUpdateOverlay(vout_display_t *vd, LPDIRECTDRAWSURFACE2 surface
     HRESULT hr = IDirectDrawSurface2_UpdateOverlay(surface,
                                                    &src, sys->display, &dst,
                                                    DDOVER_SHOW | DDOVER_KEYDESTOVERRIDE, &ddofx);
+    sys->restore_overlay = hr != DD_OK;
+
     if (hr != DD_OK) {
         msg_Warn(vd, "DirectDrawUpdateOverlay cannot move/resize overlay");
         return VLC_EGENERIC;