Long delay when locking and waking from screensaver with SVG wallpaper

[Ben High]

This bug may not be the fault of Caja. That's just my best guess for the culprit at this time.

In MATE, when locking the screen (either by using CTRL+ALT+L or System->Lock Screen), the system will wait for around 5-10 seconds before going to the screensaver. The screen does not freeze, and the cursor can still move, but clicking and typing have no effect on any open applications.

Additionally, once the computer has locked and the screensaver is being displayed, moving the mouse or pressing a key on the keyboard will cause the system to wait another 5-10 seconds before displaying the password prompt. During this period, the screensaver will continue to play as if nothing has happened.

This problem only seems to occur when there is an SVG file set as the desktop background. This does not happen with PNG or JPG backgrounds.

To replicate:
1. Set an SVG file as the background image. In theory, any SVG file should work.
2. Lock the screen either with CTRL+ALT+L or System->Lock Screen.
3. When the screensaver appears, move the mouse or press a key on the keyboard.

Expected result:
The screen will immediately (or with a very short delay) lock when the user locks the screen, and should immediately (or with a very short delay) display the password prompt when being woken from the screensaver.

Actual result:
The system pauses for around 5-10 seconds between the user locking the screen and the screensaver appearing, and the screen pauses for another 5-10 seconds between the user moving the mouse/pressing a key and the system waking from the screensaver.

System information:
Description: Ubuntu 17.10
Release: 17.10

caja:
  Installed: 1.18.4-0ubuntu2
  Candidate: 1.18.4-0ubuntu2
  Version table:
 *** 1.18.4-0ubuntu2 500
        500 http://us.archive.ubuntu.com/ubuntu artful/universe amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: caja 1.18.4-0ubuntu2
ProcVersionSignature: Ubuntu 4.13.0-21.24-generic 4.13.13
Uname: Linux 4.13.0-21-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.6
Architecture: amd64
CurrentDesktop: MATE
Date: Sun Dec 24 14:12:19 2017
InstallationDate: Installed on 2017-11-29 (25 days ago)
InstallationMedia: Ubuntu-MATE 17.10 "Artful Aardvark" - Release amd64 (20171018)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: caja
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

[Expired for caja (Ubuntu) because there has been no activity for 60 days.]