[gtk] shadow cache: Remove outdated comments

[Matthias Clasen <matthiasc src gnome org>]

commit e46a7ca70687b7ef15c237815bfe3f9269fc3956
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Oct 12 17:06:39 2019 -0400

    shadow cache: Remove outdated comments
    
    No comments are better than outdated comments.

 gsk/gl/gskglshadowcache.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
---
diff --git a/gsk/gl/gskglshadowcache.c b/gsk/gl/gskglshadowcache.c
index d2a5010a80..537989b805 100644
--- a/gsk/gl/gskglshadowcache.c
+++ b/gsk/gl/gskglshadowcache.c
@@ -1,7 +1,7 @@
 
 #include "gskglshadowcacheprivate.h"
 
-#define MAX_UNUSED_FRAMES (16 * 5) /* 5 seconds? */
+#define MAX_UNUSED_FRAMES (16 * 5)
 
 typedef struct
 {
@@ -62,9 +62,6 @@ gsk_gl_shadow_cache_begin_frame (GskGLShadowCache *self,
 {
   guint i, p;
 
-  /* We remove all textures with used = FALSE since those have not been used in the
-   * last frame. For all others, we reset the `used` value to FALSE instead and see
-   * if they end up with TRUE in the next call to begin_frame. */
   for (i = 0, p = self->textures->len; i < p; i ++)
     {
       CacheItem *item = &g_array_index (self->textures, CacheItem, i);