[gnome-shell] Revert "texture-cache: Use image-missing image when no other icon was loaded"

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit fecc0c06acacabf11befd8d1e15c8328613d25d7
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Mar 25 16:40:47 2020 +0100

    Revert "texture-cache: Use image-missing image when no other icon was loaded"
    
    The commit broke StIcon's :fallback-gicon property, as it relies on failure to load
    an icon to determine that the fallback should be shown.
    
    Luckily StIcon is the only user of st_texture_cache_load_gicon() (at least in
    regular shell code), so we'll be able to implement the 'image-missing' fallback
    there.
    
    This reverts commit 3dd8ffc2bb1cefd603bcadabd8886dda3192dbd5.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1127

 src/st/st-texture-cache.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)
---
diff --git a/src/st/st-texture-cache.c b/src/st/st-texture-cache.c
index adffafabaa..850c0d6979 100644
--- a/src/st/st-texture-cache.c
+++ b/src/st/st-texture-cache.c
@@ -34,8 +34,6 @@
 #define CACHE_PREFIX_FILE "file:"
 #define CACHE_PREFIX_FILE_FOR_CAIRO "file-for-cairo:"
 
-#define IMAGE_MISSING_ICON_NAME "image-missing"
-
 struct _StTextureCachePrivate
 {
   GtkIconTheme *icon_theme;
@@ -996,15 +994,7 @@ st_texture_cache_load_gicon (StTextureCache    *cache,
                                                    size, scale,
                                                    lookup_flags);
   if (info == NULL)
-    {
-      /* Do not give up without even trying to pick the image-missing fallback icon. */
-      info = gtk_icon_theme_lookup_icon_for_scale (theme,
-                                                   IMAGE_MISSING_ICON_NAME,
-                                                   size, scale,
-                                                   GTK_ICON_LOOKUP_USE_BUILTIN);
-      if (info == NULL)
-        return NULL;
-    }
+    return NULL;
 
   gicon_string = g_icon_to_string (icon);
   /* A return value of NULL indicates that the icon can not be serialized,