Daniel Garcia Moreno authored Jun 03, 2019 and Georges Basile Stavracas Neto committed Jul 30, 2019

We're storing in the texture cache images and scaled images appending
the scaling factor to the key. When a file changes the cache key
corresponding to that file is removed, but not the keys for the scaled
ones so that images in the cache are never reloaded.

This patch removes all keys from the cache related to the file that
changes, including those with the scaling factor.

A new hash table was added to keep track of the cached files scales, so
for a file stored with the key "KEY" we store in the new cache the
scales of this file that we've in the cache:

 * KEY -> [1.000000, 2.000000, ...]

When the KEY is removed from the cache, we can look now in this new hash
table and for each scale we also remove the key "KEY1.000000",
"KEY2.000000", etc.

GNOME/gnome-shell!567