Fix code relating to cookies

internal/icons/fallback/icon.go

@@ -505,11 +505,12 @@ func (this *iconSet) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Textur
 	}
 }
 
-func (this *iconSet) Close () {
+func (this *iconSet) Close () error {
 	if this.atlasSmall != nil {
 		this.atlasSmall.Close()
 	}
 	if this.atlasLarge != nil {
 		this.atlasLarge.Close()
 	}
+	return nil
 }